To determine a fault of a work vehicle.

A crane work vehicle 1 which raises a luffing jib 7 using a jib wire 15 wound around a jib winch 12 includes a jib angle detection part 22 which is provided to the luffing jib 7 and detects the angle of the luffing jib 7 brought under the raising control for determination on an overload or prevention control; an auxiliary raising angle acquisition part 52 which acquires the angle of the luffing jib 7 brought under the raising control from a payoff length of the jib wire 15; and an error determination part 53 which determines a fault when the difference between the detected angle and the acquired angle exceeds a predetermined error.