To provide an OFDM demodulating device which is unaffected by a delay wave exceeding a guard interval and which can suppress the calculation amount.

M (M<N) complex digital signals are extracted from a reception signal, and N complex signals are obtained by adding N-M complex signals lacking. Processing is performed at an FFT 12, and L subcarrier numbers which are not null carriers are selected. Temporary determination is performed thereto at a symbol temporary determining portion 20, and N-L 0's are inserted corresponding to a null carrier number into L complex signals at a null carrier inserting portion 31. M symbols are extracted after an IFFT 32, and the remaining N-M are 0. If these are processed at a fast-Fourier-transformer 34 and a carrier selecting portion 35, replica composed of L complex numbers which is different from an output of a matching filter portion 10 a little can be made. If an output of the symbol temporary determining portion 20 is subtracted by a subtracter 36, interference components of each subcarrier are obtained, and they are reduced from the output of a matching filter portion 10 by a subtracter 40, each subcarrier signal with accuracy higher than the output of the matching filter portion 10 can be obtained.