A vehicle control device has first and second transmission circuits that communicate by radio with a portable unit and also has a control section that, when the portable unit is confirmed to be correct, engages in a permission mode that permits the start of an engine. The first and second transmission circuits transmit first and second request signals from first and second transmission antennas to first and second communicatable areas respectively. When a back door is detected to be open, the control section does not permit the start of the engine even if an ID code signal is returned from the portable unit in response to the second request signal.