PURPOSE: To define demodulated data even when reception data is delayed by comparing time width measured in first and second level intervals with a reference time, and adjusting the sampling timing of transfer data corresponding to a result of comparison.

CONSTITUTION: A leading edge detector 1a and a trailing edge detector 1b detect the leading edge and trailing edge of the transfer data 5 consisting of a PWM symbol and PWH data received via a data transmission line. Also, an H level counter 11a and an L level counter 11b measure the H level interval and L level interval of the data 5. Measured H level interval and L level interval are compared with an H level interval and an L level interval decided in a communication system in advance by an H level width comparison part 12a and an L level width comparison part 12b. A sampling clock selector 14 adjusts a sampling timing corresponding to the result of comparison, and demodulates received data 5. Thereby, it is possible to define the demodulated data even when the rise and fall time of the data 5 are delayed by a stray capacitor and a resistor on the transmission line.