To provide a bearing integrated type resin pulley improving the durability of a bearing and preventing the peeling from a pulley body.

A symbol (t) shows the radial average wall thickness of an outer ring 27, namely, a track part wall thickness, and (r) shows an average radius of the outer ring 27 to the track part wall thickness (t), namely, the average wall thickness radius. The track part wall thickness / the average wall thickness radius (t/r) is set from the conventional level of a little less than 0.8 to 0.15, so that a displacement / an eccentric load becomes approximately 1/6 of the conventional level.