PURPOSE: To heighten the accuracy of cutting-off, by clamping each blade under a force smaller than the clamping force of a pinch-holding member, at both ends of the blade whereon spacers are arranged.

CONSTITUTION: The plural blades 11 and pinch-holding members 12 of a multiblade saw are fitted in the groove 21 of a wall 20a and secured together by the first clamping means 24 composed of contact metal members 14 and lockup bolts 22. A spacer 13 is provided between the pinch-holding members 12. Since the blades 11 are erected along the spacers 13, the blades 11 are prevented from becoming nonparallel with each other due to the deformation of the members 12. The degree of parallelism between the blades 11 is thus heightened. The spacers 13 and the blades 11 can be clamped into tight contact with each other because the blades 11 are clamped by the clamping means 25 of a restrictor composed of the spacers 13 and the second clamping members 25 after the blades 11 are pulled. This results in heightening the accuracy of cutting-off.