Abstract: In a socket portion of an endoscopic light source connector, a rod end holder is mounted on a riser plate within a housing of a light source for holding and supporting a fore end portion of a light guide rod of a light source connector, which has a proximal end portion of a light guide encased in a rigid pipe. The rod end holder is constituted by a fixed tubular casing which is mounted on the riser plate in an aligned position relative to an optical axis of illumination light path from a source lamp of the light source, and a slide member which is axially slidably fitted in the fixed tubular casing and internally provided with a light guide passage for passing illumination light from the source lamp.