A crusher includes a walking device and a crushing device, the crushing device comprises a motor, a speed reducer, a frame, a driven wheel, a driving wheel, a tensioning wheel, a chain and a roller; the motor is mounted on the frame, the speed reducer drives the driving wheel to rotate, the output shaft of the speed reducer is provided with a bearing seat, the bearing seat is obliquely placed, a plane of the base is vertical to a connection line of the center of the driving wheel and he corresponding driven wheel; two columns of crushing hammers are spirally distributed on the outer wall of the roller, wherein the axis is used as the axe, included angles of two adjacent crushing hammers, distributed on the circumference of the outer wall are equal, the crusher avoids the shear of bearing base fastening bolts, caused by horizontal component of the acting force of the chain to the driving wheel, weakens vibration when the machine works, and prolongs the service life of the crusher.