A modulator subjects an input signal to primary modulation to generate a primary modulated signal. A transmitter generates and transmits a transmission signal based on a secondary modulated signal generated from the primary modulated signal. A retransmission request receiver receives a retransmission request that contains identification information. An operator uses a data sequence that is a set of elements of a same number as a number of elements in an input signal identified by the identification information and with element values of 1 or 0 to generate operation data whose elements are values of exclusive OR of respective elements of the input signal and respective elements of the data sequence that are at same positions as positions of the respective elements of the input signal. If a retransmission request receiver receives a retransmission request, the modulator and transmitter perform the above processing using the operation data as an input signal.