To improve a bonding power between diamond grains and a WC-base cemented carbide matrix and to obtain excellent properties required of a wear resistant member by incorporating specific amounts of diamond grains, coated with a high melting point metal coating layer of specific thickness, into a WC- base cemented carbide.

In a composite material consisting of diamond grains and a WC-base cemented carbide, the content of the diamond grains is regulated to 3 to 50 vol.%. These diamond grains have coating layer composed of at least one metal and having 0.05 to 1 μm film thickness. When a metal, which has >1300°C melting point and consists of at least one element selected from the group consisting of Ir, Pt, Rh, Cr, Mo, and W, is used as the metal of the coating layer, the hard member hardly causing falling off of the diamond grains and excellent in strength can be obtained. Moreover, when at least one element selected from C, Co, and W is allowed to diffuse into the coating layer, the bonding power between the diamond grains and the WC-base cemented carbide can be increased to a greater extent. It is preferable to perform sintering of the hard member at about 1300 to 1450°C.