To easily improve abrasion resistance property in a low cost without fixing hard metal and without executing surface process by burying particles having abrasion resistance property on a surface layer part, and integratedly forming a hardening layer on a surface.

Particles 7 having abrasion resistance property and lubricating property and which is made of either one kind or two or more kinds of mixture such as molybdenum disulfide, calcium fluoride, beryllium fluoride, tungsten disulfide on a surface layer part, are buried on a full surface of a spring retainer 6 made of aluminum alloy, and a hardening layer 8 is integratedly fixed. The hardening layer 8 is formed, and thereby, abrasion on an inner circumferential surface of a taper shaped fitting hole 6a fitted to a cotter as well as on a lower surface of an outward flange 6a with which an upper end of a valve spring is brought into pressure-contact is suppressed to a minimum. It is thus possible to suppress abrasion of a pressure contact surface of the valve spring and the cotter fitting hole to the minimum without fixing hardening metal and without executing surface process and the like.