A demodulating apparatus and a demodulating method includes a correlation detector for detecting a correlation between a guard section of the symbol of a digital orthogonal frequency division multiplex modulated signal and a section having a correlation with the guard section in an effective symbol of the symbol, a section integrator for section integrating a detected output of the correlation detector with respect to the guard section, a peak detector for detecting a peak of a triangular wave signal from the section integrator, and a frame timing signal producing circuit for producing a frame timing signal of a predetermined frame of each of the frames based on a peak detecting signal from the peak detector. The frame synchronizing signal generator circuit may be made synchronized by a frame timing signal from the frame timing signal producing circuit.