diff --git a/src/shrpx_config.cc b/src/shrpx_config.cc
index 807b8067..247b2368 100644
--- a/src/shrpx_config.cc
+++ b/src/shrpx_config.cc
@@ -515,8 +515,16 @@ std::vector<LogFragment> parse_log_format(const char *optarg) {
 
     if (type == SHRPX_LOGF_NONE) {
       if (util::istartsWith(var_name, var_namelen, "http_")) {
-        type = SHRPX_LOGF_HTTP;
-        value = var_name + str_size("http_");
+        if (util::streq("host", var_name + str_size("http_"),
+                        var_namelen - str_size("http_"))) {
+          // Special handling of host header field.  We will use
+          // :authority header field if host header is missing.  This
+          // is a typical case in HTTP/2.
+          type = SHRPX_LOGF_AUTHORITY;
+        } else {
+          type = SHRPX_LOGF_HTTP;
+          value = var_name + str_size("http_");
+        }
       } else {
         LOG(WARN) << "Unrecognized log format variable: "
                   << std::string(var_name, var_namelen);
diff --git a/src/shrpx_config_test.cc b/src/shrpx_config_test.cc
index 6af69645..5138dba4 100644
--- a/src/shrpx_config_test.cc
+++ b/src/shrpx_config_test.cc
@@ -62,10 +62,11 @@ void test_shrpx_config_parse_header(void) {
 }
 
 void test_shrpx_config_parse_log_format(void) {
-  auto res = parse_log_format(R"($remote_addr - $remote_user [$time_local] )"
-                              R"("$request" $status $body_bytes_sent )"
-                              R"("${http_referer}" "$http_user_agent")");
-  CU_ASSERT(14 == res.size());
+  auto res =
+      parse_log_format(R"($remote_addr - $remote_user [$time_local] )"
+                       R"("$request" $status $body_bytes_sent )"
+                       R"("${http_referer}" $http_host "$http_user_agent")");
+  CU_ASSERT(16 == res.size());
 
   CU_ASSERT(SHRPX_LOGF_REMOTE_ADDR == res[0].type);
 
@@ -96,13 +97,18 @@ void test_shrpx_config_parse_log_format(void) {
   CU_ASSERT(0 == strcmp("referer", res[10].value.get()));
 
   CU_ASSERT(SHRPX_LOGF_LITERAL == res[11].type);
-  CU_ASSERT(0 == strcmp("\" \"", res[11].value.get()));
+  CU_ASSERT(0 == strcmp("\" ", res[11].value.get()));
 
-  CU_ASSERT(SHRPX_LOGF_HTTP == res[12].type);
-  CU_ASSERT(0 == strcmp("user-agent", res[12].value.get()));
+  CU_ASSERT(SHRPX_LOGF_AUTHORITY == res[12].type);
 
   CU_ASSERT(SHRPX_LOGF_LITERAL == res[13].type);
-  CU_ASSERT(0 == strcmp("\"", res[13].value.get()));
+  CU_ASSERT(0 == strcmp(" \"", res[13].value.get()));
+
+  CU_ASSERT(SHRPX_LOGF_HTTP == res[14].type);
+  CU_ASSERT(0 == strcmp("user-agent", res[14].value.get()));
+
+  CU_ASSERT(SHRPX_LOGF_LITERAL == res[15].type);
+  CU_ASSERT(0 == strcmp("\"", res[15].value.get()));
 
   res = parse_log_format("$");
 
diff --git a/src/shrpx_log.cc b/src/shrpx_log.cc
index ec8b27e8..b1f435e6 100644
--- a/src/shrpx_log.cc
+++ b/src/shrpx_log.cc
@@ -158,14 +158,38 @@ Log::~Log() {
 
 namespace {
 template <typename OutputIterator>
-std::pair<OutputIterator, size_t> copy(const char *src, size_t avail,
-                                       OutputIterator oitr) {
-  auto nwrite = std::min(strlen(src), avail);
+std::pair<OutputIterator, size_t> copy(const char *src, size_t srclen,
+                                       size_t avail, OutputIterator oitr) {
+  auto nwrite = std::min(srclen, avail);
   auto noitr = std::copy_n(src, nwrite, oitr);
   return std::make_pair(noitr, avail - nwrite);
 }
 } // namespace
 
+namespace {
+template <typename OutputIterator>
+std::pair<OutputIterator, size_t> copy(const char *src, size_t avail,
+                                       OutputIterator oitr) {
+  return copy(src, strlen(src), avail, oitr);
+}
+} // namespace
+
+namespace {
+template <typename OutputIterator>
+std::pair<OutputIterator, size_t> copy(const std::string &src, size_t avail,
+                                       OutputIterator oitr) {
+  return copy(src.c_str(), src.size(), avail, oitr);
+}
+} // namespace
+
+namespace {
+template <size_t N, typename OutputIterator>
+std::pair<OutputIterator, size_t> copy_l(const char (&src)[N], size_t avail,
+                                         OutputIterator oitr) {
+  return copy(src, N - 1, avail, oitr);
+}
+} // namespace
+
 namespace {
 const char LOWER_XDIGITS[] = "0123456789abcdef";
 } // namespace
@@ -212,46 +236,57 @@ void upstream_accesslog(const std::vector<LogFragment> &lfv,
       std::tie(p, avail) = copy(lgsp.remote_addr, avail, p);
       break;
     case SHRPX_LOGF_TIME_LOCAL:
-      std::tie(p, avail) = copy(time_local.c_str(), avail, p);
+      std::tie(p, avail) = copy(time_local, avail, p);
       break;
     case SHRPX_LOGF_TIME_ISO8601:
-      std::tie(p, avail) = copy(time_iso8601.c_str(), avail, p);
+      std::tie(p, avail) = copy(time_iso8601, avail, p);
       break;
     case SHRPX_LOGF_REQUEST:
       std::tie(p, avail) = copy(lgsp.method, avail, p);
-      std::tie(p, avail) = copy(" ", avail, p);
+      std::tie(p, avail) = copy_l(" ", avail, p);
       std::tie(p, avail) = copy(lgsp.path, avail, p);
-      std::tie(p, avail) = copy(" HTTP/", avail, p);
-      std::tie(p, avail) = copy(util::utos(lgsp.major).c_str(), avail, p);
+      std::tie(p, avail) = copy_l(" HTTP/", avail, p);
+      std::tie(p, avail) = copy(util::utos(lgsp.major), avail, p);
       if (lgsp.major < 2) {
-        std::tie(p, avail) = copy(".", avail, p);
-        std::tie(p, avail) = copy(util::utos(lgsp.minor).c_str(), avail, p);
+        std::tie(p, avail) = copy_l(".", avail, p);
+        std::tie(p, avail) = copy(util::utos(lgsp.minor), avail, p);
       }
       break;
     case SHRPX_LOGF_STATUS:
-      std::tie(p, avail) = copy(util::utos(lgsp.status).c_str(), avail, p);
+      std::tie(p, avail) = copy(util::utos(lgsp.status), avail, p);
       break;
     case SHRPX_LOGF_BODY_BYTES_SENT:
-      std::tie(p, avail) =
-          copy(util::utos(lgsp.body_bytes_sent).c_str(), avail, p);
+      std::tie(p, avail) = copy(util::utos(lgsp.body_bytes_sent), avail, p);
       break;
     case SHRPX_LOGF_HTTP:
       if (downstream) {
         auto hd = downstream->get_request_header(lf.value.get());
         if (hd) {
-          std::tie(p, avail) = copy((*hd).value.c_str(), avail, p);
+          std::tie(p, avail) = copy((*hd).value, avail, p);
           break;
         }
       }
 
-      std::tie(p, avail) = copy("-", avail, p);
+      std::tie(p, avail) = copy_l("-", avail, p);
+
+      break;
+    case SHRPX_LOGF_AUTHORITY:
+      if (downstream) {
+        auto &authority = downstream->get_request_http2_authority();
+        if (!authority.empty()) {
+          std::tie(p, avail) = copy(authority, avail, p);
+          break;
+        }
+      }
+
+      std::tie(p, avail) = copy_l("-", avail, p);
 
       break;
     case SHRPX_LOGF_REMOTE_PORT:
       std::tie(p, avail) = copy(lgsp.remote_port, avail, p);
       break;
     case SHRPX_LOGF_SERVER_PORT:
-      std::tie(p, avail) = copy(util::utos(lgsp.server_port).c_str(), avail, p);
+      std::tie(p, avail) = copy(util::utos(lgsp.server_port), avail, p);
       break;
     case SHRPX_LOGF_REQUEST_TIME: {
       auto t = std::chrono::duration_cast<std::chrono::milliseconds>(
@@ -265,31 +300,31 @@ void upstream_accesslog(const std::vector<LogFragment> &lfv,
       sec += ".";
       sec += frac;
 
-      std::tie(p, avail) = copy(sec.c_str(), avail, p);
+      std::tie(p, avail) = copy(sec, avail, p);
     } break;
     case SHRPX_LOGF_PID:
-      std::tie(p, avail) = copy(util::utos(lgsp.pid).c_str(), avail, p);
+      std::tie(p, avail) = copy(util::utos(lgsp.pid), avail, p);
       break;
     case SHRPX_LOGF_ALPN:
       std::tie(p, avail) = copy(lgsp.alpn, avail, p);
       break;
     case SHRPX_LOGF_SSL_CIPHER:
       if (!lgsp.tls_info) {
-        std::tie(p, avail) = copy("-", avail, p);
+        std::tie(p, avail) = copy_l("-", avail, p);
         break;
       }
       std::tie(p, avail) = copy(lgsp.tls_info->cipher, avail, p);
       break;
     case SHRPX_LOGF_SSL_PROTOCOL:
       if (!lgsp.tls_info) {
-        std::tie(p, avail) = copy("-", avail, p);
+        std::tie(p, avail) = copy_l("-", avail, p);
         break;
       }
       std::tie(p, avail) = copy(lgsp.tls_info->protocol, avail, p);
       break;
     case SHRPX_LOGF_SSL_SESSION_ID:
       if (!lgsp.tls_info || lgsp.tls_info->session_id_length == 0) {
-        std::tie(p, avail) = copy("-", avail, p);
+        std::tie(p, avail) = copy_l("-", avail, p);
         break;
       }
       std::tie(p, avail) =
@@ -298,11 +333,11 @@ void upstream_accesslog(const std::vector<LogFragment> &lfv,
       break;
     case SHRPX_LOGF_SSL_SESSION_REUSED:
       if (!lgsp.tls_info) {
-        std::tie(p, avail) = copy("-", avail, p);
+        std::tie(p, avail) = copy_l("-", avail, p);
         break;
       }
       std::tie(p, avail) =
-          copy(lgsp.tls_info->session_reused ? "r" : ".", avail, p);
+          copy_l(lgsp.tls_info->session_reused ? "r" : ".", avail, p);
       break;
     case SHRPX_LOGF_NONE:
       break;
diff --git a/src/shrpx_log.h b/src/shrpx_log.h
index d08f1bec..2fae8d04 100644
--- a/src/shrpx_log.h
+++ b/src/shrpx_log.h
@@ -118,6 +118,7 @@ enum LogFragmentType {
   SHRPX_LOGF_STATUS,
   SHRPX_LOGF_BODY_BYTES_SENT,
   SHRPX_LOGF_HTTP,
+  SHRPX_LOGF_AUTHORITY,
   SHRPX_LOGF_REMOTE_PORT,
   SHRPX_LOGF_SERVER_PORT,
   SHRPX_LOGF_REQUEST_TIME,