To improve the mounting stress withstanding the reaction of the crushing power of a material to be crushed bitten by a split blade.

A couple of first and second crushing disks having a crushing gap of specified width are relatively erected. At least one between the first and second disks is made free to rotate, a collar receiver 52 of specified height is integrally provided on the outer periphery of the base 51 of the first and second crushing disks on the crushing face 40 side, split blades 57, 57a, etc. are detachably attached to the base 51 through pedestals 56, 56a, etc., the outer peripheries of the pedestals 56, 56a, etc. are arranged in contact with the inner periphery of the collar receiver 52. Consequently, even if the crushing stress of a material to be crushed bitten by the pedestals 56, 56a, etc., and blades 57, 57a, etc. acts on the pedestals 56, 56a, etc., the outer peripheries of the pedestals 56, 56a, etc. are supported by the receiver 52 in contact, and the stress is shared with the mounting positions of the pedestals 56, 56a, etc., and the receiver 52.