To provide a drainage structure of a vehicular lamp that can eliminate water drain and prevent generation of rust of a vehicle body panel in a simple structure.

In the drainage structure of a trunk lid lamp (a vehicular lamp) 1 which is fitted to a vehicle body panel 10 wherein a gasket 11 is fitted around an opening 10A, in a state in which an outer lens 3 is pressure-welded to the gasket 11, a drainage strap 9 is intercalated between the outer lens 3 of the trunk lid lamp 1 and the gasket 11. The drainage strap 9 is composed of woven wool or resin fibrous thread. Further, the drainage strap 9 is stuck to the outer lens 3 of the trunk lid lamp 1 with a double-sided tape.