diff --git a/src/shrpx_config.cc b/src/shrpx_config.cc
index 8d23b9ac..1e023d18 100644
--- a/src/shrpx_config.cc
+++ b/src/shrpx_config.cc
@@ -1738,7 +1738,7 @@ int parse_config(const char *opt, const char *optarg,
                  << strerror(errno);
       return -1;
     }
-    mod_config()->user = strcopy(pwd->pw_name);
+    mod_config()->user = pwd->pw_name;
     mod_config()->uid = pwd->pw_uid;
     mod_config()->gid = pwd->pw_gid;
 
diff --git a/src/shrpx_config.h b/src/shrpx_config.h
index c7a3ef59..03b3700b 100644
--- a/src/shrpx_config.h
+++ b/src/shrpx_config.h
@@ -583,7 +583,7 @@ struct Config {
   ConnectionConfig conn;
   ImmutableString pid_file;
   ImmutableString conf_path;
-  std::unique_ptr<char[]> user;
+  ImmutableString user;
   std::unique_ptr<char[]> mruby_file;
   char **original_argv;
   char **argv;
diff --git a/src/shrpx_worker_process.cc b/src/shrpx_worker_process.cc
index f7dacc7c..8d09b5d2 100644
--- a/src/shrpx_worker_process.cc
+++ b/src/shrpx_worker_process.cc
@@ -64,7 +64,7 @@ void drop_privileges(
 #endif // HAVE_NEVERBLEED
     ) {
   if (getuid() == 0 && get_config()->uid != 0) {
-    if (initgroups(get_config()->user.get(), get_config()->gid) != 0) {
+    if (initgroups(get_config()->user.c_str(), get_config()->gid) != 0) {
       auto error = errno;
       LOG(FATAL) << "Could not change supplementary groups: "
                  << strerror(error);
@@ -86,7 +86,7 @@ void drop_privileges(
     }
 #ifdef HAVE_NEVERBLEED
     if (nb) {
-      neverbleed_setuidgid(nb, get_config()->user.get(), 1);
+      neverbleed_setuidgid(nb, get_config()->user.c_str(), 1);
     }
 #endif // HAVE_NEVERBLEED
   }