A light receiving device comprising: a 90 degrees hybrid circuit arranged to receive an optical signal fed into the light receiving device and a local oscillation optical signal and to mix the optical signal and the local oscillation optical signal per two polarized waves at right angles to each other, and to output optical signals of a real part and an imaginary part of two polarized waves; a plurality of photoelectric conversion circuits (30a, 30b, 30c, 30d) arranged to respectively receive optical signals of the real part and the imaginary part of two polarized waves at right angles to each other output from the 90 degrees hybrid circuit and to convert the optical signals into a plurality of electrical signals; a plurality of converters (40a, 40b, 40c, 40d) respectively arranged to digitalize the plurality of electrical signals with a given sampling clock frequency; a plurality of fixed distortion compensators arranged to compensate an output signal of each converter (81,86) for waveform distortion with a fixed compensation amount that is different from each other; a plurality of phase shift detector circuits arranged to detect a sampling phase shift from the ouput signals of the plurality of the fixed distortion compensators; a phase-adjusting-amount determiner arranged to determine a sampling phase adjusting amount by using a combined signal of the ouput signals of the plurality of the phase shift detector circuits; and a phase adjusting circuit arranged to reduce a phase difference between the sampling clock frequency and the received optical signal based on a determination result of the phase-adjusting-amount determiner. a 90 degrees hybrid circuit arranged to receive an optical signal fed into the light receiving device and a local oscillation optical signal and to mix the optical signal and the local oscillation optical signal per two polarized waves at right angles to each other, and to output optical signals of a real part and an imaginary part of two polarized waves; a plurality of photoelectric conversion circuits (30a, 30b, 30c, 30d) arranged to respectively receive optical signals of the real part and the imaginary part of two polarized waves at right angles to each other output from the 90 degrees hybrid circuit and to convert the optical signals into a plurality of electrical signals; a plurality of converters (40a, 40b, 40c, 40d) respectively arranged to digitalize the plurality of electrical signals with a given sampling clock frequency; a plurality of fixed distortion compensators arranged to compensate an output signal of each converter (81,86) for waveform distortion with a fixed compensation amount that is different from each other; a plurality of phase shift detector circuits arranged to detect a sampling phase shift from the ouput signals of the plurality of the fixed distortion compensators; a phase-adjusting-amount determiner arranged to determine a sampling phase adjusting amount by using a combined signal of the ouput signals of the plurality of the phase shift detector circuits; and a phase adjusting circuit arranged to reduce a phase difference between the sampling clock frequency and the received optical signal based on a determination result of the phase-adjusting-amount determiner.