To provide a power control unit which controls the rotating speed of a cooling fan by determining the driving voltage supplied to the fan according to the state in an electronic equipment such as temperature.

An interruption control part 175 monitors whether or not a measured value outputted from a temperature sensor 18 exceeds a predetermined value and initiates a system interruption(SMI) indicating that the value exceeds the predetermined value in such a case to inform the CPU of that. When a command is sent from the CPU in response to the system interruption, this command is accepted by a command register 173 and a voltage controller 174 controls the driving voltage supplied to the cooling fan according to the command that the command registers 173 has accepted. Consequently, rotating speed control over the cooling fan based upon the measured value of the temperature sensor is performed.