PURPOSE: To preform a heat treatment for surface hardening free from defects by the effect of heat at a low cost by remelting the plural spot-like parts arranged zigzag when viewed in a sliding direction on the surface of a cast iron sliding member by using a high energy density source.

CONSTITUTION: Plural pieces of spot-like beads 6 arranged zigzag in the direction of an axial line 5 along the outside circumferential surface of a cast iron sliding member 3 which is a cam shaft or the like are remelted by using a high energy density source such as TIG arcs. By said method the hardened surface free from strains, etc. is obtained on the outside circumferential surface. Since the effect of heat applied upon the sliding member is reduced, the rate of stock removal after the treatment is decreased.