A bearing is provided to have sufficient durability even when CVT fluid having a low viscocity is used, with its flow rate kept small, so that the efficiency of the belt-type continuously variable transmission is improved.The material of the races including the outer race 4 is made of a iron-base alloy containing, by weight, C of from 0.15% to 0.5%, Si of 0.1% to 1.5%, Mn of 0.1% to 1.5%, and Cr of 0.5% to 3.0%. This material is subjected to carbonitriding, quenching, tempering and quenching finish. The surface portion of the outer raceway 6 on the inner peripheral surface of the outer race 4 is formed with a surface layer containing C of from 0.8 weight % to 1.2 weight % and N of from 0.05 weight % to 0.50 weight %.