A PSK demodulator using a time-to-digital converter includes: a filter unit that performs band pass filtering on a PSK signal; an amplitude limiting unit that limits the amplitude of an output signal of the filter unit; a clock signal generating unit that generates a clock signal; and a time-to-digital converter that samples the phase of an output signal of the amplitude limiting unit according to the clock signal and outputs a digital signal having a value corresponding to the phase of the PSK signal. Power consumption can be reduced and a circuit implementation can be simplified.