PURPOSE: To attain an exchangeability of mutual positions between a contrast roll and a base stock by a stationary blade supporting member which supports a stationary blade having lateral shearing action and whose position is firmely held.

CONSTITUTION: A bending disk 19 is arranged partially overlapped below a stationary blade supporting member 33, turned and moved laterally below the member, and the mutual positions between a contrast roll 20 and a base stock 11 is exchanged. A movable blade holder 30 is included in the upper part of the stationary blade supporting member 33, is fixed in a guide cylinder 29 having mutual relation with a fixed blade 34, and is able to vibrate on a rear vibrating pivot. The movable holder 30 holds a movable blade 26, and the movable blade 26 moves in cooperation with a central running route through which the base stock passes. An actuator is fixed to a sliding block 32, and toward the fixed point generates pressing force. Shearing action is attained by shifting laterally the movable blade holder 30 toward the fixed blade supporting member 34.