To provide a waterproofing structure which can protect a drive unit in a water-tight state and which can establish the water-tight state without raising the manufacturing cost.

A waterproofing structure 10 includes: an opening 31 at one end; a power supply unit cover 15 formed to cover a power supply unit 11 in a water-tight state; an opening 32 at another end; a drive unit cover 17 formed to cover a drive unit 12 in a water-tight state. One end of the power supply unit 11 is provided with a supporting tube section 18 protruding on the side of the drive unit 12 as well as a protective tube section 19 formed outward in the radial direction of the supporting tube section 18 at a prescribed distance. An opening edge section 16 of the drive unit cover 17 is to be fitted into the space between the supporting tube section 18 and the protective tube section 19 in a water-tight state. An opening peripheral edge section 27 of the drive unit cover 17 and the protective tube section 19 are both covered by an opening edge section 14 of the power supply unit cover 15 in a water-tight state.