A light source device and a method of manufacturing a light source device are provided. The light source device includes a base. A light-emitter is above the base. A cap is joined to the base to cover the light-emitter. The cap includes an opening in a position corresponding to the light-emitter. A first light guide is in communication with the opening for guiding, to outside of the cap, light emitted by the light-emitter. A first ferrule is provided around the first light guide. The first ferrule is joined to an edge of the opening in a state in which the first ferrule is in the opening.