diff --git a/hbmqtt/mqtt/pingreq.py b/hbmqtt/mqtt/pingreq.py
index f886ec7..31ae9c9 100644
--- a/hbmqtt/mqtt/pingreq.py
+++ b/hbmqtt/mqtt/pingreq.py
@@ -12,7 +12,7 @@ class PingReqPacket(MQTTPacket):
         if fixed is None:
             header = MQTTFixedHeader(PacketType.PINGREQ, 0x00)
         else:
-            if fixed.packet_type is not PacketType.DISCONNECT:
+            if fixed.packet_type is not PacketType.PINGREQ:
                 raise HBMQTTException("Invalid fixed packet type %s for PingReqPacket init" % fixed.packet_type)
             header = fixed
         super().__init__(header)