Even if background noise is present, it is possible to control a guard interval length so that a minimum required SINR can be obtained. An OFDM communication device (10) includes: a correlation calculation unit (14) for calculating a correlation between a series of symbols to be received and a held signal that has a waveform identical to a waveform of a known signal contained in the series of symbols; a desired signal power acquisition unit (19) for acquiring a desired signal power based on a calculation result; a background noise power acquisition unit (22) for acquiring a background noise power that indicates a difference amount between a reception power of each of the series of symbols and the desired signal power; and a GI length determination/instruction unit (23) for determining the guard interval length in accordance with the background noise power and instructing a transmitter to transmit the series of symbols with the determined guard interval length.