To provide a crusher capable of lengthening a cutter gap adjustment interval time and enhancing the operability, and a self-traveling type crushing device on which the crusher is loaded.

A plurality of cutters (20) and spacers 21 are alternately fitted into first and second shafts (10, 11), are butted to a stepped part (12) provided on the first and second shafts (10, 11) and are tightened from a shaft end part by the cutter gap prevention mechanism (30). In the tightening by the cutter gap prevention mechanism (30), a washer (31) and a tightening member (32) having a cylindrical part (33) and a flange part (34) are fitted from the outside of a bearing (3) and a disc spring (37) is provided between the washer (31) and the flange part (34). The flange part (34) is pressed by a tip end of an adjustment bolt (42) screwed to a plate (40) tightened to a shaft end and the cutter (20) and the spacer (21) are tightened by a sum of force of the tightening member (32) and the disc spring (37).