A bearing rotatably supports an axle and is held by an axle support. The bearing includes a bearing body having an oil groove, an inlet and an outlet. Lubricating oil is supplied into and held in the oil groove through the inlet. The oil groove is formed in an inner circumferential surface of the bearing body so as to extend in a circumferential direction of the bearing body. The bearing body is held by an inner circumferential surface of the axle support with an outer circumferential surface of the bearing body in contact with the inner circumferential surface of the axle support. The outlet is opened to an axial end of the bearing body for allowing the lubricating oil in the oil groove to be discharged from the bearing body.