To provide a crusher for e.g. concrete structures allowing use as both an apparatus for cobbing work and a grain refining apparatus and attached to the tip of an arm of a work truck, e.g. a back hoe.

The crushing surface of a movable jaw section 3 is equipped with a grain edge which is square and has a plate-shaped crushing surface and a plurality of rugged teeth, and the crushing surface of a fixed jaw section is also equipped with a plate-shaped grain edge 2a having a plurality of rugged teeth. A target material is grain-refined through an opening-and-closing operation of the jaws, and the grain-refined crushed product is sorted by a sieve-equipped shroud 2b mounted.