A precoding weight generation method involves generating a channel matrix having channel state information transmitted as feedback from mobile stations undergoing spatial multiplexing for each cell that base stations manage, and generating precoding weights. When data transmission is targeted for a first mobile station that transmits the channel state information as feedback as well as transmits the channel state information to a weight generation target cell that is a target for generation of precoding weights, precoding weights are generated so as not to suppress interference on a second mobile station that transmits the channel state information as feedback as well as transmits the channel state information to the weight generation target cell, while suppressing interference on a third mobile station that does not transmit the channel state information as feedback except to the weight generation target cell.