An optical scanning system including an optical scanning device, and a photoreceiver device. The optical scanning device includes: a first waveguide array including a plurality of first waveguides; and a first phase shifter for adjusting phases of light propagating through the plurality of first waveguides to change an emission direction of emission light from the plurality of first waveguides. The photoreceiver device includes: a second waveguide array including a plurality of second waveguides configured to receive reflected light and propagate the received reflected light; and a second phase shifter for adjusting phases of the received reflected light propagating through the plurality of second waveguides to change a reception direction of the reflected light received by the plurality of second waveguides. An array pitch of the plurality of first waveguides in the optical scanning device differs from an array pitch of the plurality of second waveguides in the photoreceiver device.