PURPOSE: To make the thickness of a bush as thin as possible at a low cost and to eliminate the production of a burrs by forming the recess of an oil sump by the contraction of synthetic resin at the time of forming at the surface of the synthetic resin corresponding to the recess of a cylindrical member in a bush utilized for an automatic tensioner for adjusting the tension of a timing belt, etc. for an automobile.

CONSTITUTION: A groove 13 is formed on the bush formed surface 11e of a fixing member 11. Synthetic resin is injected and molded at the outside thereof. A bush 16 is thereby formed. At this time, if the shape, the size, the condition of injection-molding of the fixing member 11 and the bush 16 are properly selected, an oil sump groove 17 is formed on the surface of the bush 16 corresponding to the groove 13 of the fixing member 11. Thus, while the synthetic resin can flow, the thickness of the bush 16 can be thin, at a low cost, and the possibility of the production of burrs is eliminated.