This paper demonstrates a millimeter-wave (50~60 GHz) dual-conversion down-converter using fundamental Schottky diode mixer in the low-cost 0.18μm CMOS technology. The demonstrated down-converter uses two double-balanced passive mixer with dual-conversion configuration. The first down-converted stage down-converts 50~60 GHz signal to the 10 GHz and the second down-converted stage down-converts 10 GHz to the baseband with the IF bandwidth of 100 MHz. As a result, the conversion gain is around 5 dB when the LO1 power is 11 dBm and the LO2 power is 10 dBm in the 50~60 GHz operating frequency. Besides, the noise figure is about 20 dB. The totally current consumption is 32.8 mA at 2.5 Vvoltage supply.