Rolling bearing

摘要

A rolling bearing including a rolling element made of steel is provided. The rolling element has a hardness of 620 to 750HV in its interior. The rolling element is so constructed that the hardest point may exist within a depth of 10% of its diameter from a rolling contact surface of the rolling element, and that the hardness at this point is made higher by 20 to 150HV than the hardness in the interior.