PURPOSE: To operate by a clock frequency faster than the maximum clock frequency by which a conventional synchronous counter can be operated.

CONSTITUTION: A counter part 1 executes count-up by a clock signal (a) and outputs a counter value (d), a count detecting part 2 outputs a carry output request signal (b) at the time when the counter value (d) becomes a value of ((all 1)-1), and a carry output part 3 outputs a carry signal (c) by synchronizing with the next clock signal (a) to which the carry output request signal (b) is inputted.