PURPOSE: To realize secure and simultaneous clamping of a plurality of rod- shaped works (W), (W),... by using a wise (B).

CONSTITUTION: Rod-shaped works (W), (W),... are clamped through a positioning block on the front surface of which a plurality of V-shaped grooves 11c, 11c,... are formed, and a pushing block 20 where a plurality of hydraulic pistons 22, 22,... corresponding to the V-shaped grooves 11c, 11c,... are built in. The hydraulic pistons 22, 22,... moves forward and backward to each other through the oil within an enclosed oil chamber H2, and absorb the diversification of the outer diameters of the rod-shaped works W, W,... resulting in application of uniform clamping forces for every rod-shaped work W, W,....