To provide a waterproof case preventing dropping-off of a mounting screw when the mounting screw is loosened, and capable of improving working efficiency when a cover element is temporary removed.

A throttle case comprises a case body 1 capable of storing an operating portion 7 of a throttle inside; the covering element 2 blocking the opening of the case body 1, and forming a storage space S inside; a packing interposed between the covering element 2 and the case body 1 to seal the storage space S; a screw hole nc formed at an opening edge portion 1a of the case body 1, and formed with a female screw shape screwed with the mounting screw N on an inner peripheral surface; and screw insertion holes na, nb formed at positions corresponding to the screw hole nc on the covering element 2 and the packing 9, and in which the mounting screw N is inserted. The screw insertion hole nb formed on the packing 9 can be fitted with a thread of the inserted mounting screw N.