A condenser microphone apparatus which is used for a radio apparatus in order to reduce noises generated due to radiation of a high frequency signal of a transmitting unit. A series resistor is provided between a bypass capacitor provided between a drain and a source of an FET and a microphone signal output transmission line in order to prevent a high frequency voltage from being increased due to a resonance of the bypass capacitor and microphone signal output transmission line. Thus, the noises due to the radiation of the high frequency signal can be reduced.