Plating processing method of gripping surface of gripping tool, and gripping tool

A plating processing method of a gripping surface of a gripping tool, the method comprising:

• placing the gripping tool in a bottom of a first plating solution, which is an electroplating solution containing nickel ion as a main ingredient, so that the gripping surface becomes horizontal, placing, on the gripping surface, a plurality of first diamond grains having a uniform grain diameter in a quantity that covers the gripping surface, and temporarily fixing the first diamond grains onto the gripping surface by depositing nickel on the gripping surface in a state where the gripping surface is made stationary until a position relationship between the gripping surface and the first diamond grains is not displaced even when the gripping tool is moved;
• removing first diamond grains that are not temporarily fixed after the first diamond grains have been temporarily fixed, placing, in a bottom of a second plating solution that is an electroplating solution containing nickel ion as a main ingredient or an electroless plating solution forming a nickel alloy film with auto-catalysis, the gripping tool in such a way that the gripping surface becomes horizontal, and adhering the first diamond grains onto the gripping surface by further depositing a metal containing nickel within the second plating solution on the gripping surface in a uniform thickness that does not exceed the first grain diameter;
• and
• placing a plurality of second diamond grains having a second grain diameter smaller than the first grain diameter onto a metal surface of the gripping surface on which the first diamond grains are not present and which is to be formed by depositing further metal containing nickel, and adhering the second diamond grains onto the metal surface by further depositing the further metal containing nickel within the second plating solution on the metal surface in a uniform thickness that does not exceed the first grain diameter and the second grain diameter until a position relationship between the metal surface and the second diamond grains is not displaced even when the gripping tool is moved.