diff --git a/aiogram/bot/api.py b/aiogram/bot/api.py
index 675626ac..9589c3e5 100644
--- a/aiogram/bot/api.py
+++ b/aiogram/bot/api.py
@@ -24,11 +24,17 @@ def check_token(token: str) -> bool:
     :param token:
     :return:
     """
+    if not isinstance(token, str):
+        message = (f"Token is invalid! "
+                   f"It must be 'str' type instead of {type(token)} type.")
+        raise exceptions.ValidationError(message)
+
     if any(x.isspace() for x in token):
-        raise exceptions.ValidationError('Token is invalid!')
+        message = "Token is invalid! It can't contains spaces."
+        raise exceptions.ValidationError(message)
 
     left, sep, right = token.partition(':')
-    if (not sep) or (not left.isdigit()) or (len(left) < 3):
+    if (not sep) or (not left.isdigit()) or (not right):
         raise exceptions.ValidationError('Token is invalid!')
 
     return True
diff --git a/tests/test_bot/test_api.py b/tests/test_bot/test_api.py
index c5193bcc..29418169 100644
--- a/tests/test_bot/test_api.py
+++ b/tests/test_bot/test_api.py
@@ -1,18 +1,32 @@
 import pytest
-from aiogram.bot.api import check_token
 
+from aiogram.bot.api import check_token
 from aiogram.utils.exceptions import ValidationError
 
-
 VALID_TOKEN = '123456789:AABBCCDDEEFFaabbccddeeff-1234567890'
-INVALID_TOKEN = '123456789:AABBCCDDEEFFaabbccddeeff 123456789'  # Space in token and wrong length
+INVALID_TOKENS = [
+    '123456789:AABBCCDDEEFFaabbccddeeff 123456789',  # space is exists
+    'ABC:AABBCCDDEEFFaabbccddeeff123456789',  # left part is not digit
+    ':AABBCCDDEEFFaabbccddeeff123456789',  # there is no left part
+    '123456789:',  # there is no right part
+    'ABC AABBCCDDEEFFaabbccddeeff123456789',  # there is no ':' separator
+    None,  # is None
+    12345678,  # is digit
+    {},  # is dict
+    [],  # is dict
+]
 
 
-class Test_check_token:
+@pytest.fixture(params=INVALID_TOKENS, name='invalid_token')
+def invalid_token_fixture(request):
+    return request.param
+
+
+class TestCheckToken:
 
     def test_valid(self):
         assert check_token(VALID_TOKEN) is True
 
-    def test_invalid_token(self):
+    def test_invalid_token(self, invalid_token):
         with pytest.raises(ValidationError):
-            check_token(INVALID_TOKEN)
+            check_token(invalid_token)