To provide a sufficient abrasion resistance in a cam sliding contact member even if a base material of the cam sliding contact member is made of aluminum by dispersing a diffusing material to a tappet main body and the cam sliding contact member respectively, and joining the tappet main body and the cam sliding contact member with each other through a diffusion layer in which a layer of only the diffusion material is not remained substantially.

Isothermal solidification is carried out by diffusion reaction between a liquid phase diffusion material 6 and a base material, and a diffusion layer 9 which is formed uniformly by dispersing the base material and the diffusion material 6 each other is formed between a tappet main body 1 and a cam sliding contact member 7. The tappet main body 1 and the base material of the cam sliding contact member 1 are made of aluminum so as to form the diffusion layer 9 of uniform texture, whose strength is nearly equal to the base material. The tappet main body 1 and the cam sliding contact member 7 are strongly joined with each other through the diffusion layer 9, and are formed as nearly the same integrated material on the quality of a material and strength.