PROBLEM TO BE SOLVED: To efficiently release heat generated due to light emission of a light-emitting device in an endoscope apparatus.SOLUTION: An endoscope apparatus 1 includes a substantially-cylindrical insertion part 10. In the endoscope apparatus 1, an LED illumination part 37 is arranged on the tip of the insertion part, and an observation part 5 provided with a CCD 53 is arranged on the rear side of the LED illumination part 37. A part of the optical lens 51 constituting the observation part 5 has thermal conductivity and is mounted on an optical system receiver 35 which has thermal conductivity and is arranged in the vicinity of the rear side of an LED 372-1. The rear surface of the optical system receiver 35 is brought into close contact with the front surface of a mirror frame 21 having thermal conductivity. On the rear surface side of the mirror frame 21, a sheet-like heat radiation member 28 is arranged so that the longer direction is along the axial direction of the insertion part 10 in a state where the front surface is brought into contact with the rear surface side of the mirror frame 21.
