Abstract: It is made possible to use a lens array including common lenses as a lens array that collects beams of light from light-emitting units, regardless of the number of light-emitting elements included in each light-emitting unit, thereby reducing the manufacturing cost of a light-emitting device. The light-emitting device includes a substrate, light-emitting units arranged on the substrate, and a lens array including lenses provided corresponding to the light-emitting units, respectively, to collect beams of emission light from the respective light-emitting units, the lens array being arranged on the light-emitting units. Each of the light-emitting units has light-emitting elements that are mounted on the substrate in a lattice pattern and are series-parallel connected to one another in a mount region whose shape is common in the light-emitting units so as to include a predetermined number of series connections and a predetermined number of parallel connections which are set for the light-emitting unit.