PURPOSE: To improve assemblage in addition to maintaining freedom from impairing waterproofing or rattling prevention quality.

CONSTITUTION: Regarding waterproof electrical equipment formed out of a cylindrical casing 1, a chassis 3 having components such as a battery 5 and a motor 4 mounted on one side and inserted in the casing 1 from one open end thereof, and covers for closing both end openings of the casing 1, a chassis cover 30 is formed in such a way as jointed to one side of the chassis 3 for concealing the components mounted thereon, and inserted in the casing 1, together with the chassis 3. According to this construction, the rattling of the components due to a gap thereof formed with the internal surface of the casing 1 can be prevented with the cover 30.