In a cylindrical roller bearing 20 for continuously variable belt and pulley transmissions which is used at rotational support portions of a continuously variable belt and pulley transmission and in which a plurality of cylindrical rollers 23 are rollably provided in a circumferential direction between an outer ring 21 and an inner ring 22, a raceway surface 23a of the cylindrical roller 23 is made to take the shape of a full crowning, and a radius curvature R of the full crowning is made to satisfy a relationship of 0.01.ltoreq.L.sup.2/(Da.times.R).ltoreq.0.03 relative to a diameter Da and a roller length L of the cylindrical roller 23.