To provide a mobile station apparatus and a communication system that realize an efficient transmission control for a base station apparatus to allocate resources of the PUSCH with appropriate AMC mode in accordance with the channel feedback report and the scheduling request from the mobile station apparatus, and also enable rapid transmission of the uplink data (enable rapid transmission of the UL-SCH) when the mobile station apparatus transmits only the channel feedback report. A mobile station apparatus 200 applied to a system in which a base station apparatus 100 allocates the physical uplink shared channel and the mobile station apparatus 200 transmits uplink data using the physical uplink shared channel, transmits to the base station apparatus 100 the scheduling request requesting the base station apparatus 100 to allocate resources for transmitting the uplink data, using the physical uplink shared channel.