diff --git a/src/settings_list.rs b/src/settings_list.rs
index ad00081..b4d1eff 100644
--- a/src/settings_list.rs
+++ b/src/settings_list.rs
@@ -1,12 +1,18 @@
 use crate::gettext;
 use crate::settings::SettingDes;
 use crate::settings::JsonValueType;
+use json::JsonValue;
 
 pub fn get_settings_list() -> Vec<SettingDes> {
     vec![
         SettingDes::new("refresh_tokens", gettext("Pixiv's refresh tokens. Used to login."), JsonValueType::Str, None).unwrap(),
         SettingDes::new("cookies", gettext("The location of cookies file. Used for web API."), JsonValueType::Str, None).unwrap(),
         SettingDes::new("language", gettext("The language of translated tags."), JsonValueType::Str, None).unwrap(),
-        SettingDes::new("retry", gettext("Max retry count if request failed."), JsonValueType::Number, None).unwrap(),
+        SettingDes::new("retry", gettext("Max retry count if request failed."), JsonValueType::Number, Some(check_u64)).unwrap(),
     ]
 }
+
+fn check_u64(obj: &JsonValue) -> bool {
+    let r = obj.as_u64();
+    r.is_some()
+}