A terminal device receives a control channel including a DCI format and transmits a PUSCH, in which the DCI format includes an uplink index and information for indicating a HARQ process number; when both a first bit and a second bit of the uplink index are set to 1, the HARQ process number in the PUSCH corresponding to the first bit is X and the HARQ process number in the PUSCH corresponding to the second bit is mod (X+1, Z); the mod (X+1, Z) is a function outputting a remainder when dividing (X+1) by Z; the X is determined based on the information for indicating the HARQ process number; and the Z is a value identical to a maximum number of HARQ processes in a serving cell determined by an uplink/downlink configuration.