A base station device, which allocates one or more subbands of each of an uplink and a downlink to a mobile station device and transmits response information, which indicates whether or not uplink data from the mobile station device has been properly received, to the mobile station device, the base station device includes: a control unit (11) which controls an arrangement of a response information group including multiple pieces of response information directed to a downlink subband allocated to the mobile station device; and a multiplexing unit (160) which collects the same type of multiple pieces of response information to configure the response information group, and arranges the configured response information group in the downlink subband based on the control of the control unit.