PURPOSE: To provide a lift cylinder stroke regulating device which has high regulating workability and a pull-off preventing function.

CONSTITUTION: The head part of the piston rod 6 of a shift cylinder is fitted in a recessed part 10 formed on the under surface side of the upper beam 4 of an inner mast 4, and annular grooves 11 and 15 positioned facing each other are respectively formed in the fit-in surface thereof. A stopper ring 19 for preventing pull-off of the piston rod 6 is located in the annular grooves 11 and 15 and a regulation margin to allow relative vertical movement of the stopper ring 19 is set at an annular groove 15 on the rod side. A regulating bolt 13 capable of making contact with the upper end face of the piston rod 6 is mounted on the upper surface side of the upper beam 4. By screwing forward and backward the regulating bolt, the assembly position of the piston rod 6 to the upper tie beam 4 is regulated.