A light-emitting device includes a base that extends in one direction; a light-emitting unit in which multiple light sources that are disposed in the one direction are supported by a supporting body that extends in the one direction and that is formed from a metal block; a spacer that is interposed between the base and the light-emitting unit in a direction of an optical axis of each light source; and a fixing unit that fixes the light-emitting unit to the base in a mode in which a compressive load is applied to the spacer.