To perform different carrier measurement without degrading throughput.

A packet continuation judging part 121 observes user packet data and judges whether the packet addressed to own station is continuously received or it is paused. A different-carrier measurement suppressor 122 generates the signal for permitting different-carrier measurement if the packet continuation judging part 121 indicates a judging result of packet pausing while generating no signal for permitting different-carrier measurement if the judging result does not indicate continuation of packets. If the different-carrier measurement is permitted, a different-carrier reception timing setting part 112 notifies the timing for switching carrier to a carrier switching control unit 113 and a carrier reception quality measuring part 110. The carrier switching control unit 113 controls switching of carrier at an RF reception part 102 at that timing, and the carrier reception quality measuring part 110 measures reception quality of the carrier that has been switched.