An aim is to provide a light source device that can be assembled more easily than conventional light source devices. A light source device 100 comprises a light emitting module 150, a mount 140, a lighting unit 110, and a case 120, wherein the lighting unit 110 has a pair of pin terminals 112a and 112b, each of the mount 140 and a substrate 151 of the light emitting module 150 has a pair of through-holes 154a and 154b, and a pair of feed terminals 153a and 153b are disposed at positions of the substrate 151 corresponding to the through-holes 154a and 154b, the pair of pin terminals 112a and 112b being electrically connected to the pair of feed terminals 153a and 153b by penetrating through the through-holes 154a and 154b of the mount 140 and the substrate 151.