An optical phased array device according to at least one embodiment includes a light distribution unit configured to branch a traveling path of light, input through an input terminal, at least twice, and to direct distributed pieces of sub-light to a plurality of output terminals; at least one light modulator configured to form a plurality of channels by modulating phases of the pieces of sub-light; at least one first amplifier in an optical path between the input terminal and the at least one light modulator, the at least one first amplifier configured to amplify at least a piece of sub-light; at least one first complementary amplifier configured to replace the at least one first amplifier; and a switch configured to switch the first complementary amplifier in or out of the optical path between the input and the at least one light modulator.