PURPOSE: To obtain the titled cermet preventing the damage of its whole body due to a crack by carrying out sintering so that a cermet substrate is composed of a dense surface layer of a proper thickness and a porous inner part having pores which account for a proper area.

CONSTITUTION: High toughness cermet is obtd. by carrying out sintering so that a cermet substrate 1 such as the substrate of an insert is composed of a dense surface layer 2 of 0.01W2.00mm thickness T and a porous inner part 3 having pores which account for 10W50% of the surface area of the sintered body. When the dense surface layer 2 is cracked by a shock, the propagation of the crack C1 toward the inside is hindered by pores, so the damage of the whole body of the high toughness cermet can be prevented. The average diameter of the pores in the porous inner part 3 is 0.5W5μm.