An optical scanning device includes: first and second mirrors; an optical waveguide layer disposed between the first and second mirrors; a pair of electrodes sandwiching the optical waveguide layer; and a driving circuit that applies a voltage to the pair of electrodes. The first mirror emits part of light propagating through the optical waveguide layer to the outside. The optical waveguide layer contains a liquid crystal material or an electrooptical material. The alignment direction of the liquid crystal material or the direction of a polarization axis of the electrooptical material is parallel or perpendicular to the direction in which the optical waveguide layer extends. The driving circuit applies the voltage to the pair of electrodes to change the refractive index of the liquid crystal material or the electrooptical material to thereby change the light emission direction.