A receiving device receives a transmission unit signal that is sent from a sending end and accommodates a result of dividing, the result of the dividing being obtained by quantizing a value based on relative differences between a plurality of sampling values having temporal prior-posterior relationship therebetween, and dividing data produced in a time series in accordance with a result of the quantizing, at the sending end. The receiving device includes a need-of-adjustment determining means which determines whether or not an amplitude adjustment needs to be made in accordance with a value of an amplitude of a signal waveform indicated by a decoding result of the produced data accommodated in the transmission unit signal; and an amplitude adjusting means which transparently passes the signal waveform when the need-of-adjustment determining means determines that the amplitude adjustment does not need to be made, and performs predetermined amplitude adjusting processing to pass the signal waveform when the need-of-adjustment determining means determines that the amplitude adjustment needs to be made.