PURPOSE: To prevent the unexpected full open of cutting pliers in the locked state by providing holes in the upper grip and stop lever of the cutting pliers in such a constitution that both the holes are superposed to each other in an identical point when the cutting pliers are locked, and inserting a pin to the holes.

CONSTITUTION: A hole 6 is formed in the middle part of the upper grip 2 of cutting pliers 1, and a hole 6' is formed in the upper part of the stop lever 5 of the cutting pliers 1. The holes 6, 6' are constituted in such a manner that the holes are superposed to each other to form one through hole, when the upper grip 2 is pressed down to bring the cutting pliers 1 into the locked state. In this state, a pin or nail is inserted into the through holes 6, 6'. Consequently, even if the lever is touched at the time of work, the cutting pliers remain locked by the identical force until the pin is released, and safety is improved.