PURPOSE: To safely operate a hydraulic working vehicle by computing a warning territory, stroke end of a cylinder, and the like by the controller of a working vehicle based on signals from various sensors such as an inclination sensor, and outputting warnings according to respective warning territories.

CONSTITUTION: The controller 25 of a hydraulic working vehicle provided with an ultralong attachment 13 having a crusher 19 and the like is connected to various sensors such as an inclination sensor 27 of a body, an approach sensor 32 for the stroke end of a bucket cylinder, and the other sensors 28-31. Based on the signals from these respective sensors, the distance L and the height H from the extreme end part 18 of an arm to the center O of a turning body 11 are computed, the result is displayed on a display machine 26, and when the vehicle enters the warning territory for preventing falling down or the stroke end of the bucket cylinder 24, warnings are output by respective different tones, also in case of wire connection troubles, intermittent sound, or the like from a buzzer 38 or an alarm unit 39. Hereby, safe operation can be carried out.