To improve an image suppression ratio in an image rejection mixer.

The image rejection mixer 1 is provided with: a square means to apply square arithmetic processing to signals of two systems respectively; an average value operation means to execute the average value operation of the square-arithmetic-processed signals, a ratio arithmetic means to calculate a ratio of the average value; a square root processing means to calculate a square root of the ratio; an amplitude multiplication means to multiply the square root to the amplitude of either of the signal with an I system and the signal with a Q system; a signal multiplication means to multiply the signals of the two systems; a square means for correcting a phase to apply the square arithmetic processing to the signals of the two systems respectively; an addition means to add the squared value, a ratio arithmetic means for correcting a phase to calculate a ratio of an output value of the signal multiplication means and an output value of the addition means; a constant multiplication means to multiply a prescribed constant to the ratio; and a phase correcting means to correct the phase of either of the signal with the I system and the signal with the Q system to be used for the second time frequency conversion on the basis of the output of the constant multiplication means.