PURPOSE: To make it possible to efficiently crush an object to be crushed by providing a first arm opening and closing cylinder between the ends opposite to crushing claws of a pair of opening and closing arms, and providing a second cylinder to vary the interval of pivoting pins in the central parts of the opening and closing arms.

CONSTITUTION: A first cylinder 2 coupled with pins is provided between the ends opposite to crushing claws 1a of a pair of opening and closing arms 1, and the connection between the central parts of the opening and closing arms 1 is made with a second cylinder 4. First of all, the second cylinder 4 is reduced from a state where the opening and closing arms 1 is open by the first cylinder 2 and the second cylinder 4, an object 7 to be crushed is crunched with the crushing claws 1a by approaching right and left providing pins 3 to each other, and when a chamber (g) on a pump side of the second cylinder 4 reaches high pressure, the first cylinder 2 is extended as shown by an arrow P, and the upper ends of the opening and closing arms 1 are moved as shown by an arrow (a) to continue crush. According to the constitution, crushes are made by the first and second cylinders 2 and 4, useless motions such as the separation and approach of the crushing claws from the crushed object during the crush are eliminated, and efficiency of crush work can be promoted.