To provide the operating-pedal lock structure of construction machinery in which safety is improved by relating a lock for the operating pedal to a lock by a cut-off lever while the lock release of the operating pedal is not conducted in the case of the lock release of the cut-off lever and discretely enabling the lock release of the operating pedal.

In the operating-pedal lock structure of the construction machinery with a driver's seat, console boxes installed to the left and the right of the driver's seat, control levers mounted on each top face of both console boxes, the cut-off lever being secured to at least one of the console boxes and being capable of locking the operation of the control lever, the operating pedal set up in front of the driver's seat and an operating-pedal locking means capable of locking the operation of the operating pedal, the operating pedal is locked by operation in the direction that the control lever is brought to a locked state in the cut-off lever, the locked state of the operating pedal is not released when the cut-off lever is operated from the locked state of the control lever to a lock-released state, and the locked state of the operating pedal is brought to the lock-released state by discrete lock-release operation.