A channel monitor detects execution data quantities of first and second receiving circuits 3 and 4 which process audio and other line switching data or packet data transmitted from a plurality of base stations. Antenna weight values calculated by an antenna weight calculator 10 and supplied to the receiving circuits 3 and 4 are variably controlled on the basis of the execution data quantities of the receiving circuits. Consequently, it becomes possible to optimize the antenna weight values used for processing the data in the receiving circuits 3 and 4, hence improving the reception quality of a terminal device.