To optimize the operation time of a heater load in accordance with the operation environment and the purpose of its use so as to reduce unnecessary load on the engine or the battery.

In response to a switch input by the user that activates a heater load (a wiper deicer 30, a rear defogger 32, or mirror heater 34), a body control unit 1 determines the vehicle's running environment including outside-air temperature, running status, and engine load status, etc., based on the information directly input thereto from a sensor switch and information of the vehicle from respective units transmitted through the medium of an in-vehicle LAN, and controls the operation regulation or suspension or, in reverse, the positive operation of the heater load. This enables optimization of operation time of the heater loads in accordance with the operation environment or the purpose of their use, and allows reduction of unnecessary loads on the engine or the battery.