A communication device includes an amplitude conversion unit configured to generate a symbol sequence according to a bit sequence, a distribution matching unit configured to add redundant bits to the symbol sequence through probabilistic amplitude shaping (PAS) coding, an insertion unit configured to insert a pilot symbol into the symbol sequence to which the redundant bits have been added and transmit the symbol sequence into which the pilot symbol has been inserted to a transmission path, and a control unit configured to acquire information on the transmission path and change, according to the information on the transmission path, allocation of the redundancy of the PAS coding and the redundancy of the pilot symbol in a range of redundancy that is able to be allocated depending on a predetermined throughput.