Patent ID: 7462128

Claim:
A rolling element having a rolling contact surface coming into rolling contact with a counterpart, the rolling element comprising: a base metal; and a nickel coat formed on a surface of the base metal and cooperating with the base metal to constitute the rolling contact surface, wherein the rolling contact surface satisfies condition that a mean value of ratios of L 1 to L 2 as measured in at least three optional observation areas is in a range of from 1.2 to 2.4, where each of the at least three optional observation areas is disposed in a cross section taken in a vertical direction relative to the surface of the base metal covered with the nickel coat and is defined by two parallel lines extending in the vertical direction; L 1 represents a length of an interface between the base metal and the nickel coat in each of the at least three optional observation areas; and L 2 represents a length of a reference line segment extending perpendicular to the vertical direction in each of the at least three optional observation areas, L 1 and L 2 being present in same observation area.