In a transmitter 2 of a communications system 1 where a wireless communication is made between the transmitter 2 and a receiver 3, an information bit generating unit generates information bits from data to be transmitted. A sub-block generating unit generates a sub-block including information bits in units. A coding unit 24 generates coded bits by merging and collectively coding sub-blocks of plural units. An antenna transmitting unit 27 generates sub-block coded bits by distributing the coded bits output from the coding unit 24, and transmits the generated sub-block coded bits to the receiver 3.