A wireless LAN base station is provided with a noise signal scanning antenna separately from a wireless signal reception antenna. An attenuation circuit section attenuates the received signal from the noise scanning antenna according to an attenuation factor from an attenuation factor storage section. A distance setting storage section stores a distance between the wireless signal reception antenna and the noise scanning antenna. An attenuation factor storage section holds pieces of data each of which indicates the relationship between the distance between the antennas and an attenuation factor in the form of a table. An attenuation circuit section employs the attenuation factor so as to attenuate the received signal from the noise signal scanning antenna. A subtraction circuit section subtracts an output signal of the attenuation circuit section from the signal from the wireless signal reception antenna, and reduces or eliminates a noise from the received signal from the wireless signal reception antenna.