To provide a light source device for an endoscope wherein a light source lamp can be easily and correctly exchanged with a simple structure.

The light source device for an endoscope includes: a light source; a support board for supporting the light source; a guide rail and a spring member attached to the support board; and a slide member slidably supported by the guide rail. The slide member has a positioning part for positioning the light source. In the light source device for an endoscope, the light source is fixed between the spring member and the support board by sliding the slide member to a predetermined position while the light source is positioned to the positioning part.