A down-conversion frequency mixer includes: a radio frequency (RF) input unit disposed between a VDD line and a GND line and configured to receive an RF signal; an LO input unit configured to receive a carrier frequency (LO) from an internal frequency synthesizer; an intermediate frequency (IF) output unit disposed in parallel to the RF input unit between the VDD line and the GND line and configured to mix the RF signal with the LO signal and output an IF signal; a current generation unit configured to generate a stabilized current without being influenced with noise entered through the VDD line and the GND line; and a noise blocking unit disposed between the VDD line and the RF input unit, between the VDD line and the IF output unit, between the GND line and the RF input unit, and between the GND line and the LO input unit and configured to copy the current generated from the current generator and generate a stabilized current.