To provide a crusher which attains miniaturization of a cylinder and is excellent in work efficiency.

This crusher is constituted so that a front inlet/outlet port 6 of working oil communicated with an hydraulic power source via a first line 14, is provided at a rear part of the front piston 5a of a front cylinder chamber 1a, and a first rear inlet/outlet port 7 of working oil communicated with the hydraulic power source is provided at a front part of the rear piston 5b of a rear cylinder chamber 1b via a second line 19, and a second rear inlet/outlet port 8 communicated with a branch line 20 of the first line 14 is provided at a rear part. The front piston 5a is linked with a drive pin 10 for opening/closing a crushing blade 2 consisting of a pair of blades 2a, 2b openably/closably pivoted thereto. A valve gear 15 is provided at an intermediate part of the first line 14 at the hydraulic power source side from the branch line 20, opening when the working oil flows toward the cylinder, and another valve gear 22 is provided on the branch line working with a higher pressure than the valve gear 15 and allowing the oil flow toward the cylinder.