A method of forming a film on the machined surface of a machine part, comprising a preparatory process for preparing a supply body formed of a metallic material softer than at least the machined surface of the machine part, a pressure welding process for connecting the supply body to the machine part by pressure-welding the end face of the supply body to the machined surface of the machine part while causing a relative rotation between the machine part and the supply body, and a cutting process for providing a soft metal layer of a specified thickness on the machined surface of the machine part by cutting the supply body in the direction approximately perpendicular to the axis of the relative rotation in the vicinity of a joint position between the machined part and the supply body.
