To obtain wear resistance, strength and oil impregnating performance in practical use by making an oil-impregnated sintered bush have specific sintered density, and forming at least the inner peripheral surface of a roller coming in contact with the outer peripheral surface of the oil-impregnated sintered bush, of resin.

An oil-impregnated sintered bush 2 has a tendency to be improved in oil impregnating performance but lowered in mechanical strength in case of reducing sintered density, and to be heightened in mechanical strength but lowered in oil impregnating performance in case of increasing sintered density. An oil-impregnated sintered bush with sintered density in a range of 6.0g/cm3-7.1g/cm3 combining sufficient mechanical strength and oil impregnating performance in practical use is therefore used as the oil-impregnated sintered bush 2. On the other hand, resin such as engineering plastic high in mechanical strength is used as material of a roller fitted to the outer periphery of the oil-impregnated sintered bush 2. Polyoxymethylene, polyamide, or the like is generally used from the viewpoint of mechanical strength and wear resistance. In case of needing heat resistance, polyphenylene sulfide, polyetherimide, polyvinylidene fluoride, or the like can be used.