To perfectly prevent an electronic apparatus from condensing in the inside, at cooling of the electronic apparatus, by utilizing Peltier effect.

A module 2 which is a heating body to be cooled and a Peltier element 3 contacted thereto to cool are disposed inside the frame of an electronic apparatus 1, which shuts off outside air from its interior. The Peltier element 3 contacts the module 2, and its heating side 3a contacts the electronic apparatus frame 9, to exchange heat from the heating side 3a through heat conduction, through a radiator 10 on the frame 9 surface. The electronic apparatus frame 9 is filled with dry air 6 introduced from an intake valve 7. A dew point meter in the electronic apparatus 1 monitors the dew point temperature in the frame, and a controller 4 controls the cooling power of the Peltier element 3, to prevent the dewing in the frame in a dew point temperature range of the dry air 6. Optimum temperature of the module 2 can be set by the controller 4.