In order to finely crush a shredable object, two rotational shafts for supporting cutting blades are provided in parallel in the transverse direction inside a shredder main body. The cutting blades that are provided with a plurality of cutting portions protruding from outer peripheral thereof are disposed in the shaft direction of the two rotational shafts so that these cutting portions engage with each other. A throw-in port for a shredable object is provided in one end portion of the rotational shafts in an upper portion of the shredder main body in the shaft direction. A discharge port for the shredable object is provided in the other end portion of the rotational shafts in a lower portion of this shredder main body in the shaft direction. Transverse feeding members for forwarding the shredable object that is thrown into the throw-in port and crushed by the cutting blades, to a discharge port side is provided and, thereby shredding the shredable object for a plurality of times inside the shredder main body.