a radio communication apparatus using a direct conversion method capable of receiving a radio signal having a predetermined frequency band . the radio communication apparatus includes : a low - noise amplifier section including one or a plurality of low - noise amplifiers receiving input of a receiving signal having a predetermined frequency band ; and a mixer section including in - phase and quadrature mixers demodulating an output of the low - noise amplifier into in - phase - component and quadrature - component signals , respectively , wherein the mixer section includes a capacitor in an input section , separates the in - phase component and the quadrature component by the capacitor , and supplies the components to the corresponding in - phase and quadrature mixers , respectively .