PURPOSE: To be good in engageability with a spindle, excellent in concentricity and to provide self-lubricating capability as well as to make it manufacturable by means of an injection molding process, by letting the sleeve form a tubular body consisting of plastics and have an almost regular polygonal cross section in the inner circumferen tial edge and a round cross section in the outer circumferential edge, respectively.

CONSTITUTION: A sleeve 1 is formed into a tubular body consisting of plastics, and the outer circumferential edge 2 is a round form in section and the inner circumferen tial edge 3 is an almost regular polygonal section, respectively. With suchlike constitu tion, each side of the outer circumference of a spindle and the inner circumference of the sleeve 1 comes to contact with each other in consequence. When this sleeve 1 is offered as a product, sectional accuracy in the inner circumferential edge is manufacturable better than the conventional round sectional one interms of accuracy and, what is more, engageability with the spindle can be made yet better. In addition, raw material is of plastics inherent in self-lubricating ability, manufacture and mainte nance both are easy, and there is nothing of any smudge due to scattering and sticking of a lubricant, thus work environment also comes to very good. Moreover, it is manufacturable accurately by means of a simple method, say, an injection molding process.