Provided are a base station apparatus, a terminal apparatus and a communication method, capable of an efficient retransmission control of uplink data of which a resource for transmission is not discerned in grant-free multiple access. A terminal apparatus configured to communicate with a base station apparatus includes a transmitter configured to transmit an identifying signal indicating that the terminal apparatus itself transmits an uplink data channel and the uplink data channel. The uplink data channel includes an uplink data bit, a bit representing an identifier of the terminal apparatus, a first error detection bit generated from the uplink data bit, and a second error detection bit generated from the identifier of the terminal apparatus. The first error detection bit is scrambled using the identifier of the terminal apparatus, and the second error detection bit is scrambled using the identifying signal.