A method for producing a cemented carbide material includes producing an M3C type double carbide (wherein M comprises M1 and M2; M1 represents one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; and M2 represents one or more elements selected from the group consisting of Fe, Co and Ni) as a main component of the surface portion; reducing heat treating the compact at a vacuum atmosphere; carburizing the resulting WC—Co compact at a temperature of 800 to 1100° C.; subjecting the carburized compact to liquid phase sintering at a temperature of more than 1350° C. to form a sintered body; and coating a surface layer of the sintered body with a compound containing boron and/or silicon and subjecting the coated sintered body to a diffusion heat treatment at a temperature within a range from 1200 to 1350° C.