diff --git a/src/shrpx.cc b/src/shrpx.cc
index a6eec5ce..9daa88eb 100644
--- a/src/shrpx.cc
+++ b/src/shrpx.cc
@@ -1168,11 +1168,11 @@ int main(int argc, char **argv)
 
   if(!get_config()->npn_list) {
     mod_config()->npn_list = parse_config_str_list(&mod_config()->npn_list_len,
-                                                   DEFAULT_NPN_LIST);
+                                                   DEFAULT_NPN_LIST).release();
   }
   if(!get_config()->tls_proto_list) {
     mod_config()->tls_proto_list = parse_config_str_list
-      (&mod_config()->tls_proto_list_len, DEFAULT_TLS_PROTO_LIST);
+      (&mod_config()->tls_proto_list_len, DEFAULT_TLS_PROTO_LIST).release();
   }
 
   if(!get_config()->subcerts.empty()) {
diff --git a/src/shrpx_config.cc b/src/shrpx_config.cc
index b9305782..8fd4c15a 100644
--- a/src/shrpx_config.cc
+++ b/src/shrpx_config.cc
@@ -229,12 +229,12 @@ void set_config_str(char **destp, const char *val)
   *destp = strdup(val);
 }
 
-char** parse_config_str_list(size_t *outlen, const char *s)
+std::unique_ptr<char*[]> parse_config_str_list(size_t *outlen, const char *s)
 {
   size_t len = 1;
   for(const char *first = s, *p = nullptr; (p = strchr(first, ','));
       ++len, first = p + 1);
-  auto list = new char*[len];
+  auto list = util::make_unique<char*[]>(len);
   auto first = strdup(s);
   len = 0;
   for(;;) {
@@ -468,11 +468,11 @@ int parse_config(const char *opt, const char *optarg)
   } else if(util::strieq(opt, SHRPX_OPT_NPN_LIST)) {
     delete [] mod_config()->npn_list;
     mod_config()->npn_list = parse_config_str_list(&mod_config()->npn_list_len,
-                                                   optarg);
+                                                   optarg).release();
   } else if(util::strieq(opt, SHRPX_OPT_TLS_PROTO_LIST)) {
     delete [] mod_config()->tls_proto_list;
     mod_config()->tls_proto_list = parse_config_str_list
-      (&mod_config()->tls_proto_list_len, optarg);
+      (&mod_config()->tls_proto_list_len, optarg).release();
   } else if(util::strieq(opt, SHRPX_OPT_VERIFY_CLIENT)) {
     mod_config()->verify_client = util::strieq(optarg, "yes");
   } else if(util::strieq(opt, SHRPX_OPT_VERIFY_CLIENT_CACERT)) {
diff --git a/src/shrpx_config.h b/src/shrpx_config.h
index 31e6ef10..df80e2d9 100644
--- a/src/shrpx_config.h
+++ b/src/shrpx_config.h
@@ -34,6 +34,7 @@
 #include <arpa/inet.h>
 #include <cstdio>
 #include <vector>
+#include <memory>
 
 #include <event.h>
 #include <openssl/ssl.h>
@@ -274,15 +275,15 @@ int load_config(const char *filename);
 std::string read_passwd_from_file(const char *filename);
 
 // Parses comma delimited strings in |s| and returns the array of
-// pointers, each element points to the each substring in |s|. The
-// number of elements are stored in |*outlen|. The |s| must be comma
-// delimited list of strings. The strings must be delimited by a
+// pointers, each element points to the each substring in |s|.  The
+// number of elements are stored in |*outlen|.  The |s| must be comma
+// delimited list of strings.  The strings must be delimited by a
 // single comma and any white spaces around it are treated as a part
-// of protocol strings. This function may modify |s| and the caller
-// must leave it as is after this call. This function allocates memory
-// to store the parsed strings and it is caller's responsibility to
-// deallocate the memory.
-char** parse_config_str_list(size_t *outlen, const char *s);
+// of protocol strings.  This function may modify |s| and the caller
+// must leave it as is after this call.  This function copies |s| and
+// first element in the return value points to it.  It is caller's
+// responsibility to deallocate its memory.
+std::unique_ptr<char*[]> parse_config_str_list(size_t *outlen, const char *s);
 
 // Copies NULL-terminated string |val| to |*destp|. If |*destp| is not
 // NULL, it is freed before copying.