A frequency mixer device is provided with a mixer circuit having an input cell that amplifies an input signal and a switching cell that mixes the amplified input signal with a switching signal and outputs a multiplied signal, and a DC offset compensator that detects the input level of the input signal and outputs a compensation signal based on that detection signal, the compensation signal being supplied to the mixer circuit so as to compensate a DC offset included in the multiplied signal. The compensation signal that the DC offset compensator outputs is added to the output signal of the input cell so as to compensate the DC offset. Low frequency noise included in the compensation signal is converted to a frequency near that of the switching signal, and does not range over the desired waveband of the mixer output.