An audio input device calculates respective degrees of coincidence between a user's vocalizations and recognition terms in a voice dictionary by speech recognition and extracts a recognition term having the highest degree of coincidence from the voice dictionary. Further, the audio input device outputs a command to operate one of installations, such as radio, CD player, air conditioner, etc. The audio input device includes a remote controller for transmitting signal waves to the installations equipped with receivers to carry out remote control of the installations. In operation, the larger the installation which the remote controller is directed to has a receiving intensity of the signal wave detected byte receiver, the larger the audio input device makes an extraction weight of the recognition terms concerned with the installation, in the voice dictionary.