PURPOSE: To provide the clock interruption detection circuit suitable for circuit integration with respect to the clock interruption detection circuit detecting the interruption of a clock sent externally.

CONSTITUTION: The circuit consists of a monitor counter 10 counting an internal clock, a flip-flop 11 receiving a carry output of the monitor counter 10 as a reset input and a detected clock as a clock respectively, a flip-flop 11 receiving a fixed value '1' as a data input, and a gate circuit 12 receiving a Q output of the flip-flop 11 as its 1st input, an output on the way of the monitor counter 10 to its 2nd input and its own output to its 3rd input, detecting clock interruption and outputting it as an error signal.