PURPOSE: To realize a digital phase indicator which can stably operate and correctly display even if waveforms include noise or difference in voltage and current amplitude exists.

CONSTITUTION: The digital phase indicator comprises range amplifiers A1, A2 to which input voltage (v) and input current (i) are respectively applied, an automatic gain adjusting circuit AGC consisting of analog multipliers X1, X2 whose output voltage is multiplied via integrators A5, A6, an analog part ANL consisting of zero-cross comparators COMP1, C0MP2 to which outputs from the automatic gain adjusting circuit AGC are respectively provided, a measurement frequency regulating circuit 9, a first counter U3 for measuring time width T2 of a signal obtained by the measurement frequency regulating circuit, 9, a second counter U4 for measuring an integrated value Σt of time corresponding to a phase angle, a calculator MCU for calculating a phase angle of AC input and a logic part LOG consisting of a flip-fop circuit FF4 to which the outputs of both zero-cross comparators COMP1, COMP2 constituting the analog part are applied.