To extend lubricant life by securing a lubricant reservoir in at least one rolling bearing and supplying a lubricant from the reservoir, in a pulley unit having rolling bearings on both sides sandwiching a one-way clutch.

This pulley unit A comprises two internal and external annular bodies 1, 2 arranged concentrically, a one-way clutch 3 interposed in an annular space between both annular bodies 1, 2, and rolling bearings 4, 5 provided on both sides of the one-way clutch 3 in the annular space. One rolling bearing 5 is a roller bearing, at least one of pockets 26 for storing rollers that are provided on several circumferential places of a cage of this roller bearing is used as a lubricant reservoir, and a lubricant is supplied from this lubricant reservoir.