To provide a mechanism to perform accurate cutting sliding and cutting by a moving blade opposite to a fixed blade without no change of the center of the moving blade when a steel bar to be cut is cut in an arbitrary spot and to perform smooth supply and release of pressure oil in an oil pressure mechanism to effect slide of the moving blade through interlocking operation by a single switch lever.

A starting switch lever 43 is situated at a part of a grasp handle 41 formed integrally with a cover body 40. A fixed cutting blade 32 and a moving cutting blade 33 are situated on the tip side and the rear side, respectively, opposite to each other at the tip part of a head frame 29, situated at the front side of a hydraulic cylinder body 2, with a recessed part 30 nipped therebetween. The vertical part on one side of the moving cutting blade is mounted on the tip part of a cylinder piston 4 and the lower end part of the vertical part on one side is fitted in the streak groove part of the inner bottom of a head frame. The hook part on the other side of the moving cutting blade is engaged with a protrusion step part formed on the rise wall on one side of the head frame, and the moving cutting blade is slid over the protrusion step part and the streak groove part.