A receiving device in a communication system that separates one frame of information bits into plural blocks, performs turbo encoding of the information bits of each block and transmits the result, and decodes the encoded information bits, where the receiving device includes plural decoders number of which is less than the number of blocks per frame. Each decoder performs a decoding process on encoded information bits of each block that have been expressed by likelihood, when a condition for stopping decoding is met, executes the decoding process of encoded information bits of another block for which decoding has not yet been performed. When the condition for stopping decoding has been met for all block before the number of times decoding has been performed for each decoder reaches a preset maximum number of repetitions, the decoding results of all the blocks are serially combined, an error detection process is executed, and when no error is detected, the decoding results are output.