PURPOSE: To obtain a brake disk applicable to rolling stock of higher speed than heretofore.

CONSTITUTION: This brake disk can be produced by casting a material where an Al-Si alloy containing 6-13% silicon is used as base phase and dispersion strengthening is done by uniformly blending silicon carbide of 3-50μm grain size with the base-phase metal by 5-30wt.%. Because silicon is contained in the molten metal, the added silicon carbide can be prevented from decomposing and forming into aluminum carbide. As a result, the deterioration in the flowability of molten metal during the pouring of molten metal can be prevented. By this method, the nondefective brake disk of complicated shape can be obtained without deteriorating castability. Even if the initial speed of braking of rolling stock is increased, friction characteristics at a level practically equal to that of the conventional brake disk can be maintained.