To provide a crushing disc minimized in the load exerted on it during crushing.

This disc comprises a disc body 10 which has (a) setting grooves 14 each having a slope having on the upper surface equally spaced jointing holes 14' for the attachment of a chipping cutter 50 for processing the objective into chips and contiguously formed on the upper surface of each open groove 12 and of each oblong hole 13, (b) fitting grooves 15 each having equally spaced bolt holes 15' on the surface, radially formed between groves 14 on the both sides of the inside bottom, and (c) rows of fixed holes 16 radially formed on the surface; seal parts 71 on the upper surface of each of which holes 71' through which bolts B bonded to the holes 16 are passed and which coincide with the holes 16; air contact parts each of which is bent outwardly of each seal part 71 and generates air eddies when the body 10 is rotated to blow the crushed objective away into the upper surface of the body 10 through the holes 13 and open holes of the body 10; and air blow brackets 70 having reinforcing ribs 73 supported in the inside of the bent part on each part 71 and each part 72.