Method and apparatus for reducing electrical power consumption of an electronic unit provided with a central processing unit (CPU). The CPU is returned to a normal operation state at regular intervals when the CPU has been placed in a sleep state. The CPU outputs a clear signal to a monitoring circuit, and makes reference to an actuation signal for an external device, such as, for example, a motor from a control switch to place the CPU in the sleep state at a time other than a time when reference is made to the clear signal and the input signal. When the CPU has been released from the sleep state, reference to an output of the clear signal and the input signal and an output of only the clear signal are repeated at regular intervals and at a predetermined frequency.