diff --git a/src/core/ngx_log.c b/src/core/ngx_log.c
index cc38b02da..a9221db6e 100644
--- a/src/core/ngx_log.c
+++ b/src/core/ngx_log.c
@@ -302,7 +302,10 @@ ngx_set_error_log_levels(ngx_conf_t *cf, ngx_log_t *log)
         }
     }
 
-    if (log->log_level == NGX_LOG_DEBUG) {
+    if (log->log_level == 0) {
+        log->log_level = NGX_LOG_ERR;
+
+    } else if (log->log_level == NGX_LOG_DEBUG) {
         log->log_level = NGX_LOG_DEBUG_ALL;
     }