diff --git a/pixivpy3/api.py b/pixivpy3/api.py
index 8a246b6..473c620 100644
--- a/pixivpy3/api.py
+++ b/pixivpy3/api.py
@@ -24,6 +24,7 @@ class BasePixivAPI:
         self.user_id: int | str = 0
         self.access_token: str | None = None
         self.refresh_token: str | None = None
+        self.token_expiration: int | None = None
         self.hosts = "https://app-api.pixiv.net"
 
         # self.requests = requests.Session()
@@ -63,6 +64,11 @@ class BasePixivAPI:
         stream: bool = False,
     ) -> Response:
         """Requests http/https call for Pixiv API"""
+        if self.token_expiration and datetime.now().timestamp() >= self.token_expiration:
+            # Token expired refresh auth.
+            print("Token expired, refreshing auth.")
+            self.token_expiration = None
+            self.auth()
         merged_headers = self.additional_headers.copy()
         if headers:
             # Use the headers in the parameter to override the
@@ -123,11 +129,12 @@ class BasePixivAPI:
         headers: ParamDict = None,
     ) -> ParsedJson:
         """Login with password, or use the refresh_token to acquire a new bearer token"""
-        local_time = datetime.now().strftime("%Y-%m-%dT%H:%M:%S+00:00")
+        local_time = datetime.now()
+        local_time_str = local_time.strftime("%Y-%m-%dT%H:%M:%S+00:00")
         headers_ = CaseInsensitiveDict(headers or {})
-        headers_["x-client-time"] = local_time
+        headers_["x-client-time"] = local_time_str
         headers_["x-client-hash"] = hashlib.md5(
-            (local_time + self.hash_secret).encode("utf-8")
+            (local_time_str + self.hash_secret).encode("utf-8")
         ).hexdigest()
         # Allow mock UA due to #171: https://github.com/upbit/pixivpy/issues/171
         if "user-agent" not in headers_:
@@ -156,6 +163,8 @@ class BasePixivAPI:
         elif refresh_token or self.refresh_token:
             data["grant_type"] = "refresh_token"
             data["refresh_token"] = refresh_token or self.refresh_token
+            if self.access_token:
+                data["access_token"] = self.access_token
         else:
             msg = "[ERROR] auth() but no password or refresh_token is set."
             raise PixivError(msg)
@@ -183,6 +192,7 @@ class BasePixivAPI:
             self.user_id = token.response.user.id
             self.access_token = token.response.access_token
             self.refresh_token = token.response.refresh_token
+            self.token_expiration = local_time.timestamp() + token.response.expires_in
         except json.JSONDecodeError:
             msg = f"Get access_token error! Response: {token}"
             raise PixivError(