A resin part for a vehicle provided with: a panel body having a design surface; and stepped reinforcing ribs, which are vertically arranged on the inside surface of the panel body, in which the wall thickness of the base end portion is formed to be thinner than the wall thickness of the leading end portion, and in which the side ends at the end in the direction in which the ribs extend (arrow (X) direction) are open. Resin supply ports, to which molten resin is supplied prior to the base end portion, are formed in the leading end portion.