A light source device includes: a substrate; a light-emitting unit matrix including a plurality of light-emitting units disposed in a matrix on the substrate; and a reflective resin disposed in a region, on the substrate, including a region where the light-emitting unit matrix is disposed. The plurality of light-emitting units include a first light-emitting unit and a second light-emitting unit adjacent to each other in a column direction of the light-emitting unit matrix. The reflective resin includes a first reflective portion disposed between the first light-emitting unit and the second light-emitting unit and extending in a direction intersecting the column direction. At least a portion of an upper surface of the first reflective portion protrudes beyond an upper surface of the first light-emitting unit and an upper surface of the second light-emitting unit.