To provide a cylindrical injection-molded article which can omit a troublesome work process for adjusting the wall thickness of a web or a rib for eliminating the uneven deformation of the peripheral part of the article to be uniform and repeating try and error with molding conditions and can easily improve the roundness of the peripheral part.

The joint between a rim and the web positioned on an extended line is formed to have a thick wall from the central part of the boss of the cylindrical injection-molded article toward a gate trace formed on the web, and the wall thickness of the joint is reduced gradually in the peripheral direction and the central direction.