PURPOSE: To obtain a phase comparator with wide phase comparison range and easy to reduce the number of circuit elements.

CONSTITUTION: A period where the difference of logic level between a first digital signal and a second digital signal is generated due to phase shift between the first and second digital signals A, B with same pattern can be distinguished from another period where the logic level of the first digital signal coincides with that of the second digital signal by the combination of two output signals E, F from first and second arithmetic and logic means 20 and 21-23, not by one signal. A DC voltage signal G in accordance with the phase difference of the first and second digital signals A, B can be obtained by those two signals E, F, and driving an integral function part consisting of two resistors 24, 25 and a capacitor 26.