When an orthogonal frequency division multiplex (OFDM) modulated signal is demodulated by discrete Fourier transformation (DFT), DFT is performed using a time window of an accurate phase synchronized with the synchronization symbol. Therefore, first, the reproduction clock is divided to generate a basic time window signal. The results of the DFT processing on the OFDM signal are used to detect the phase deviation and the phase of the basic time window signal is adjusted based on that phase deviation. Preferably, the results of DFT are used for synchronization pull-in to generate a stable time window signal. More preferably a DFT circuit for demodulating the OFDM modulated signal and a DFT circuit for generating a time window signal are provided separately.