An adapter-type endoscope includes a distal end adapter and an insertion portion. The distal end adapter includes a light-emitting device substrate and an adapter-side electrical connection portion. The insertion portion includes a distal end portion to which the distal end adapter is detachably mounted, and has an insertion portion-side electrical connection portion connected to an adapter-side electrical connection portion, and a dual-purpose wire for power supply and heat release serving as both a heat releasing wire and a power source wire. The adapter-side electrical connection portion includes an electrical connection portion main body serving as both an electrical connection portion and a heat conducting portion and whose distal end surface closely contacts the light-emitting device substrate. The insertion portion-side electrical connection portion includes an electrode serving as both an electrical connection portion and a heat conducting portion and having a close-contact surface closely contacting the electrical connection portion main body.
