PURPOSE: To enable measuring accuracy of pulse width to be improved without increasing clock frequency by measuring a pulse width using n clock signals which are phase-shifted by 1/n cycle each.

CONSTITUTION: In this circuit, a clock generator 1 generates n clock signals which are phase-shifted by 1/n cycle each and n counters 2 count up each clock. Therefore, since the pulse width can be measured using n clock signals in this circuit, measuring accuracy can be improved by n times without increasing clock frequency.