To produce a sound absorbing panel for use in a sound-proof wall, etc., of an expressway, etc., by using, as raw materials, coal ashes and waste plastics such as used PET bottles, the coal ashes and waste plastics being desired to be developed with respect to their application in large quantity.

The sound absorbing panel is formed by preparing sintered particles containing coal ashes as a raw material, and a coating material containing a waste plastic as a raw material, which covers the sintered particles, and pressure-molding the resultant particles. According to the sound absorbing panel, blowholes are formed in the molded particles and between the same. The method for producing the sound absorbing panel is carried out by granulating and sintering the coal ashes to obtain the sintered particles having the blowholes therein, and coating surfaces of the particles with the coating material containing the waste plastic as a raw material, followed by press-molding the particles. As a result, reduction of noise pollution and effective utilization of the waste materials which are causes of environmental pollution are both achieved.