To solve a problem that power is consumed by a bias current that should flow for obtaining an input signal in a microphone circuit while a voice input is waited, and that an available time of an illumination appliance is shortened when a power source is a battery, in an illuminator which can be remotely controlled in voice using an input circuit for which an electret capacitor microphone is used.

A one-chip microcontroller is used to cause a bias current intermittently to flow for operating the electret capacitor microphone, so that a standstill time is set in electrification to save the power of the battery. Thus, there are energy saving effects such that the available time of the illumination appliance is prolonged when the power source is the battery and that the use of power is saved even when a commercial power source is used.