In a wireless LAN base station device including plural antennas for making communications with a wireless terminal, plural transmission-reception portions connected to the plural antennas, plural control processors for controlling the plural transmission-reception portions, and a central processor for controlling the plural control processors, each transmission-reception portion measures a reception level or/and each control processor measures a communication error occurrence rate, and the central processor controls the plural control processors to select a transmission-reception portion so that the reception level is maximum or/and the communication error occurrence rate is minimum. The control processors cease prescribed transmission-reception portions for a time zone in which the communication load is low.