PURPOSE: To reduce the abrasion quantity of a piston which has excellent tenacity, can be manufactured at a low cost, and slides on the inner face by orienting silicon carbide whiskers on a silicon nitride matrix in the same direction as the inner face of a cylinder liner.

CONSTITUTION: In the ceramic 3 of a silicon nitride matrix 1 combined with silicon carbide whiskers 2, silicon carbide whiskers 2 are oriented nearly in the same direction as the inner face of a cylinder liner. Whiskers 2 are oriented nearly in parallel with (a), (b), (c), and (d) faces on the surface of the ceramic 3 but not in the Z direction, thus all the whiskers 2 contribute in the improvement of the shock tensile tenacity in the X direction and the Y direction parallel with the surface of the ceramic 3. Since silicon nitride is used for the matrix 1, it has excellent heat resistance, abrasion resistance, and heat shock resistance, no whisker 3 is oriented in the Z direction, end sections of hard silicon carbide whiskers 2 are rarely exposed on the surface of the cylinder liner, and the abrasion of a piston is reduced.