PURPOSE: To materialize enough waterproof in spite of its small-size and inexpensive heat radiation structure, in a charger to be mounted on an electric automobile.

CONSTITUTION: A case 1 covering the body of a charger is equipped with ventilation holes 2 and 3 for circulating inside air and outside air and a cooling fan 4 for sending outside air into the case 1 through these through ventilation holes 2 and 3 so as to cool the charger. Several ventilation holes 2 and 3 are provided with waterproof covers 21 and 22 free of opening and closing, and these waterproof covers 21 and 22 can take the first position (b) to open the ventilation holes 2 and 3 and the second position (a) to block the ventilation holes 2 and 3. Furthermore, this is equipped with a waterproof cover opening and closing means 30 for performing opening and closing of the waterproof covers 21 and 22, and this waterproof cover opening and closing means 30 shifts the waterproof covers 21 and 22 into the first position during the charge operation, in association with the connection of a charge connector 40 and its release, and shifts the waterproof covers 21 and 22 into the second position when not charging.