PURPOSE: To eliminate residual tensile stresses by use of compressive stresses so as to prolong the life of a brake drum or the like by prestressing the surface of the brake drum which is in frictional engagement with a brake pad, thus inducing compressive stresses.

CONSTITUTION: This brake drum 20 includes a flange inside face 22, an inner edge 23, an outer edge 24, a biting part 25, and a wrapping part 26 in addition to an inner surface 21 against which a brake pad is pressed. A circumferential ring 28 is provided on an outside face 27. A plurality of holes 29 are bored in the inside face 22 of the flange. In this case, the inner surface 21 of the brake drum 20 in frictional engagement with the brake pad is prestressed to induce compressive stresses. The inner surface 21 is roughened in the range of 508 to 1270 microcentimeters. Residual tensile stresses are thereby eliminated by use of the compressive stresses so as to prolong the life of the brake drum 20.