A diversity reception device includes a power combiner to combine electric powers of OFDM signals, each OFDM signal being received by a first antenna and second antenna, a switch to change connections between branched output-ports of the first and second antennas, in mid-stream of effective symbol periods, the effective symbol periods are assigned respectively in each of symbol periods of the OFDM signals, a receiver to demodulate the OFDM signals, a phase shifter to shift phases of the OFDM signals received by the second antenna, and an arithmetic and control processing circuit to calculate complex correlation coefficient between a guard interval, assigned in each of the symbol periods associated with the first antenna, and a copy-source interval, assigned in each of the symbol periods associated with the second antenna, and to determine rotation angle on the basis of the complex correlation coefficient.