An electronic endoscope 1 includes a distal end portion 11 of an insertion portion 2 which incorporates an image pickup unit 30, a first metal frame 20 which holds an observation window 22, a second metal frame 33, 35 which holds an objective optical system 32, 34, a third metal frame 36 which is made to fit with a rear portion of the second metal frame 33, 35 and holds an electronic component 42, 43, 45, 46, an anti-fogging unit 51 which prevents fogging of the observation window 22, and a non-metal thermal insulation member 56 which thermally insulates the anti-fogging unit 51 and the second metal frame 33, 35 from each other to inhibit transmission of heat generated in the anti-fogging unit 51 to the third metal frame 36. With the configuration, the electronic endoscope 1 can inhibit thermal effects of the anti-fogging unit on a solid image pickup device unit and reduce noise to obtain a clear image and has improved efficiency in preventing fogging of the objective optical system by means of the anti-fogging unit.
