To prevent the adhesion of powder and grain materials on an impact face of an impact component in an impact type pneumatic conveying crusher for carrying the powder and granular materials by compressed air, impacting them on an impact face of the impact component and crushing them.

A device is constituted of an accelerating pipe 9 for carrying and accelerating powder and granular materials by compressed air, a crushing chamber 7a communicating with an air outlet 9b on one end of the accelerating pipe and an impact component 16 having an impact face 17, on which the carried and accelerated powder and granular materials are impacted and crushed, disposed inside the crushing chamber so that the impact face faces the air outlet 9b of the accelerating pipe. An air passage with one end supported on a site on which the adhesion of the powder and grain materials on the impact face is generated is formed, and a compressed air feed means 22 for feeding the compressed air is provided on the other end of the air passage, and the compressed air is jetted out of an opening formed on the impact face to increase the air density in the vicinity of the site on which the adhesion of powder and granular materials on the impact face is generated.