This invention is about the direct conversion receiver. It is excellent the receiving sensitivity that DC off-set, matching characteristics of the relationship of I/Q circuits and noise characteristics are improved. In order to achieve this purpose, the direct conversion receiver uses vertical bipolar junction transistor available in standard triple-well CMOS technology in the switching element of mixer and base-band analog circuits. Furthermore, as using the passive mixer in the other practical example of this invention, this invention controls the occurrence of l/f noise. As using the vertical bipolar junction transistor available in standard triple-well CMOS in the base-band analog circuits, this invention realizes the direct conversion receiver that DC off-set, matching characteristics of the relationship of I/Q circuit and noise characteristics are improved.