An optical scanning device includes: a first waveguide that propagates light by total reflection; and a second waveguide. The second waveguide includes: a first multilayer reflective film; a second multilayer reflective film that faces the first multilayer reflective film; and a first optical waveguide layer directly connected to the first waveguide and located between the first and second multilayer reflective films. The first optical waveguide layer has a variable thickness and/or a variable refractive index and propagates the light transmitted through the first waveguide. The first multilayer reflective film has a higher light transmittance than the second multilayer reflective film and allows part of the light propagating through the first optical waveguide layer to be emitted to the outside. By changing the thickness of the first optical waveguide layer and/or its refractive index, the direction of the part of the light emitted from the second waveguide is changed.