PROBLEM TO BE SOLVED: To provide a stroke end detection device capable of detecting the stroke end of a derricking cylinder with inexpensive configuration.SOLUTION: A stroke end detection device is provided with a ground angle detector 11, a jack-up state detector 12 and stroke end determination means 20. The stroke end determination means 20 obtains a stroke end ground angle Θfrom a stroke end machine angle Θ, and a machine body inclining angle α being a ground angle &thetas;when the jack-up state detector 12 detects, and compares the stroke end ground angle Θwith a present ground angle &thetas;to determine the stroke end. The stroke end can be normally detected even if the machine body 30 inclines from a horizontal plane G. Since the ground angle detector 11 used for an overload protection device can be used, there is no need to install a new detector and thereby, the stroke end can be detected with inexpensive configuration.
