diff --git a/src/shrpx_config.cc b/src/shrpx_config.cc
index 3911db70..e37d84c7 100644
--- a/src/shrpx_config.cc
+++ b/src/shrpx_config.cc
@@ -151,7 +151,7 @@ bool is_secure(const StringRef &filename) {
 } // namespace
 
 std::unique_ptr<TicketKeys>
-read_tls_ticket_key_file(const std::vector<std::string> &files,
+read_tls_ticket_key_file(const std::vector<StringRef> &files,
                          const EVP_CIPHER *cipher, const EVP_MD *hmac) {
   auto ticket_keys = make_unique<TicketKeys>();
   auto &keys = ticket_keys->keys;
@@ -2451,7 +2451,7 @@ int parse_config(Config *config, int optid, const StringRef &opt,
   case SHRPX_OPTID_LISTENER_DISABLE_TIMEOUT:
     return parse_duration(&config->conn.listener.timeout.sleep, opt, optarg);
   case SHRPX_OPTID_TLS_TICKET_KEY_FILE:
-    config->tls.ticket.files.push_back(optarg.str());
+    config->tls.ticket.files.push_back(make_string_ref(config->balloc, optarg));
     return 0;
   case SHRPX_OPTID_RLIMIT_NOFILE: {
     int n;
diff --git a/src/shrpx_config.h b/src/shrpx_config.h
index a535f124..e1905d45 100644
--- a/src/shrpx_config.h
+++ b/src/shrpx_config.h
@@ -470,7 +470,7 @@ struct TLSConfig {
       int family;
       bool tls;
     } memcached;
-    std::vector<std::string> files;
+    std::vector<StringRef> files;
     const EVP_CIPHER *cipher;
     // true if --tls-ticket-key-cipher is used
     bool cipher_given;
@@ -1006,7 +1006,7 @@ FILE *open_file_for_write(const char *filename);
 // expected file size.  This function returns TicketKey if it
 // succeeds, or nullptr.
 std::unique_ptr<TicketKeys>
-read_tls_ticket_key_file(const std::vector<std::string> &files,
+read_tls_ticket_key_file(const std::vector<StringRef> &files,
                          const EVP_CIPHER *cipher, const EVP_MD *hmac);
 
 // Returns string representation of |proto|.
diff --git a/src/shrpx_config_test.cc b/src/shrpx_config_test.cc
index a3f259dd..3ec166c8 100644
--- a/src/shrpx_config_test.cc
+++ b/src/shrpx_config_test.cc
@@ -173,8 +173,8 @@ void test_shrpx_config_read_tls_ticket_key_file(void) {
 
   close(fd1);
   close(fd2);
-  auto ticket_keys =
-      read_tls_ticket_key_file({file1, file2}, EVP_aes_128_cbc(), EVP_sha256());
+  auto ticket_keys = read_tls_ticket_key_file(
+      {StringRef{file1}, StringRef{file2}}, EVP_aes_128_cbc(), EVP_sha256());
   unlink(file1);
   unlink(file2);
   CU_ASSERT(ticket_keys.get() != nullptr);
@@ -216,8 +216,8 @@ void test_shrpx_config_read_tls_ticket_key_file_aes_256(void) {
 
   close(fd1);
   close(fd2);
-  auto ticket_keys =
-      read_tls_ticket_key_file({file1, file2}, EVP_aes_256_cbc(), EVP_sha256());
+  auto ticket_keys = read_tls_ticket_key_file(
+      {StringRef{file1}, StringRef{file2}}, EVP_aes_256_cbc(), EVP_sha256());
   unlink(file1);
   unlink(file2);
   CU_ASSERT(ticket_keys.get() != nullptr);