A mobile communication system in which a mobile station apparatus transmits, to a base station apparatus, uplink data using a physical uplink shared channel assigned by an uplink data transmission permission signal, wherein the base station apparatus: transmits, to the mobile station apparatus, a radio resource control signal including a transmission instruction of reception quality information; and transmits, to the mobile station apparatus, the uplink data transmission permission signal, and wherein the mobile station apparatus: periodically transmits, to the base station apparatus, first reception quality information using a physical uplink control channel according to a transmission instruction of the reception quality information included in the radio resource control signal; transmits, to the base station apparatus, second reception quality information using the physical uplink shared channel in case that a transmission instruction of reception quality information is included in the uplink data transmission permission signal; and transmits, to the base station apparatus, the first reception quality information using the physical uplink shared channel in case that the physical uplink shared channel is assigned by the uplink data transmission permission signal which does not include a transmission instruction of the reception quality information in transmitting the first reception quality information.