PURPOSE: To constitute the processor so that a central processing unit executes a regular operation, when the central processing unit executes a clock stop in a sleep state, and an interrupting signal is informed to the central processing unit.

CONSTITUTION: This information processor is constituted of an input means 4, a RAM 2 in which input data is stored, a ROM in which a program code is stored in advance, a central processing unit 5 for executing control in accordance with the code stored in the ROM 1, an oscillating circuit 6 for supplying a clock to its central processing unit 5, a clock control circuit 7 for controlling a clock from its oscillating circuit, an interruption control circuit 8 for controlling an interrupting signal, and a time counting means 9. In such a manner, switching from a regular mode to a sleep mode, and switching from the sleep mode to the regular mode are executed in several μs, therefore, low power consumption can be realized.