Semiconductor light-emitting device, includes: substrate having base and conductive part; first to third semiconductor light-emitting elements; first to third wires connected to the first to third semiconductor light-emitting elements respectively; and light-transmitting resin part covering the first to the third semiconductor light-emitting elements, wherein the base has main and rear surfaces facing opposite sides in thickness direction of the base, wherein the conductive part includes main surface part on the main surface, wherein the main surface part includes main surface first part where the first and second semiconductor light-emitting elements are mounted, wherein the main surface first part reaches both ends of the main surface in first direction perpendicular to the thickness direction, and wherein the main surface first part is separated from both the main surface part where the third semiconductor light-emitting element is mounted and the main surface part where the first, second, and third wires are connected.