The invention belongs to the technical field of crushing machinery, and discloses a rubber crushing device which comprises a machine body and a transmission mechanism, wherein the machine body is internally provided with a crushing bucket and a collecting bucket, a first rotating shaft and a second rotating shaft are rotationally connected with the upper part of the crushing bucket, the first rotating shaft and the second rotating shaft are rotated through gears, and crushing rollers are arranged on both of the first rotating shaft and the second rotating shaft; the transmission mechanism comprises a motor, a third rotating shaft, a driving belt pulley and a driven belt pulley; the third rotating shaft is driven to rotate through a motor; the driving belt pulley is mounted on the third rotating shaft; the driven belt pulley is connected with the second rotating shaft; a belt is arranged between the driving belt pulley and the driven belt pulley; both the driving belt pulley and the driven belt pulley are cone-shaped; small diameter ends of the driving belt pulley and the driven belt pulley are in opposite directions; a shifting block is arranged on the small diameter end of the driven belt pulley; a baffle plate is arranged on the side wall of the crushing bucket; an elastic part is arranged between the baffle plate and the crushing bucket. The rubber crushing device is adoptedto solve the problem in the prior art that crushed rubber is large in particle size as current is fluctuated and weakened.