To make a crusher suitable for a collecting work of iron scraps by supporting a magnet device in which two flat permanent magnets separately arranged on different magnetic poles toward an attraction surface of a main body frame are incorporated into a mold so that the magnet device may be moved by a guide member and connecting the magnet device with the inside of the frame via a cylinder for elevating and lowering.

In a space 13 within a frame of a crusher 1 biting a material to be crushed between a fixed arm 3 and a movable arm 4, a magnet device 20 is stored and iron scraps generated according to a crushing work are attracted by an attraction surface 15a. The magnet device 20 stores a permanent magnet into a mold and the magnet device 20 is freely movably supported by a guide member 28. Suspension hardware fixed to the mold and suspension hardware 32 fixed to a main body frame 2 are connected via a cylinder 30 for elevating and lowering. The permanent magnet is arranged so that the lower surface side may be different poles N and S from each other and a line of magnetic force extending between both of the magnetic poles is made to extend from the lower surface of the magnet device 20 up to a distant place in an almost circular arc shape. Therefore, iron scraps scattered in the distance can be quickly attracted.