A wireless control apparatus for vehicles in that reduces the drain on an internal power source of a portable unit so that the internal power source can be used for a long period of time without being changed. A wireless control apparatus for vehicles including a control apparatus body provided on the vehicle side, and a portable unit carried by the driver. The portable unit has a start signal receiver for receiving a start signal from the vehicle side, a communication signal transmitter for transmitting a communication signal to the vehicle side, a controller for controlling the operation of the communication signal transmitter, and an operation power switching device for selecting between a signal power operation mode in which the portable unit operates from electric power obtained from the start signal and a power source operation mode in which the portable unit operates from an internal power source. When inoperative, the portable unit is held in the signal power operation mode. After the receipt of the start signal, the portable unit is actuated and switching to the power source operation mode is performed.