Interference suppression by beam forming is achieved even in an FDD (Frequency Division Duplex) system. A base station device 1 performs communication based on FDD. The base station device 1 includes a downlink signal reception unit 12 that receives a downlink signal transmitted from another base station device. The base station device 1 performs a beam forming process for directing a null beam to an arrival direction of the downlink signal from the another base station device, by using transmission path information between the base station device and the another base station device, the information being available from the downlink signal received by the downlink signal reception unit 12.