An electronic endoscope comprising a pick-up unit at a distal end of the electronic endoscope, the pick-up unit comprising: an object optical system that brings in image light of a portion to be observed in a body cavity; a solid-state image pick-up device that picks up the image light and outputs image pick-up signals; a cover glass disposed above an image pick-up surface of the solid-state image pick-up device with spacing secured between the cover glass and the image pick-up surface; and a prism, whose incidence plane and emission plane are connected to the object optical system and the cover glass respectively, that guides image light from the object optical system to the pick-up surface, wherein the electronic endoscope further comprises: a heater that is attached to the prism and heats a surface of the cover glass, to which the emission plane is connected, via the prism; and a controller that controls operations of the heater.