Abstract: A frequency-conversion mixer, which is designed to operate in substantially the whole range of the radio frequency band extending from low frequency to the ultra-high frequency, has first and second diodes inversely arranged in parallel connection between a first input terminal for a receiving signal and a junction point. Third and fourth diodes are connected in forward series between a common terminal and a second input terminal for an oscillator signal with the junction point between the third and fourth diodes. A dc component removing capacitor is connected to the junction point for providing a frequency mixed signal, whereby the use of a transformer as used in a double balanced mixer is eliminated and there is practically no output response at frequencies below the cutoff frequency of the diodes.