A harmonic mixer comprising an anti-parallel diode having two diodes connected in parallel in reverse directions between first and second ends, the first end receiving a local oscillation signal, and the second end receiving an information signal and a DC bias, an output signal of the harmonic mixer being available at the second end. With the capabilities of the anti-parallel diode, it is possible to realize the radio communication with the use of a high frequency range at least 30 GHz at a low cost and with a simple configuration of the harmonic mixer and the radio communication device having the same, although it is considered hard to generate the stable local oscillation frequency for the radio communication of at least 30 GHz.