A light-emitting device includes a transparent light guide plate and a light source that irradiates light onto the light guide plate, in which a plurality of dot-shaped light-emitting concave portions having light output surfaces that output incident light derived from the light source from light-emitting surfaces are formed on the light guide plate, and a diffraction grating, which is an assembly of grooves paralleled at a constant pitch, is formed on each of the light output surfaces of the dot-shaped light-emitting concave portions.