To eliminate the necessity of replacing both of a vehicle side receiver and a transmitter when adding the automatic mode function to a conventional device.

In this transmitter having a locking switch and an unlocking switch, and having a signal making means for making and outputting a locking signal or an unlocking signal corresponding to operation according to the operation of the locking switch or the unlocking switch, the signal making means generates either signal of the locking signal or the unlocking signal for a specific time when judging that either of the locking switch and the unlocking switch is operated in a mode different from normal operation, and finishes generation of the locking signal or the unlocking signal with the lapse of the specific time.