A communication apparatus and a communication method capable of suppressing an increase of bits used for a request to send a reference signal and flexibly setting a resource used for sending a reference signal. In a base station, a transmission processing unit transmits, in one of a plurality of formats, control information containing a request to send a sounding reference signal (A-SRS), and a reception processing unit receives the transmitted A-SRS using the resource specified by the format of the transmitted control information. Then, the plurality of formats is associated with each different SRS resource by a setting unit.