PURPOSE: To obtain an outrigger device capable of contriving spreading a departure angle of a vehicle and avoiding interference with each other between a car body side member and a 'float.

CONSTITUTION: A float 30 in lower ends of jack cylinders 24, by a slide supporting mechanism X arranged therebetween, can be moved in almost a horizontal direction between a position at use time and a position at storage time in a car width directional inner side from the position at use time and further to a side of the other outrigger. Thus at the time of an outrigged condition of outrigger devices 4, 7, by setting the float of a pair of outriggers 5, 6 and 8, 9 respectively to the position at use time, a landing load applied to each float 30 can be surely supporter. At the time of a storage condition of the outrigger devices 4, 7, by setting each float 30 respectively to the position at storage time, an extending amount of each float 30 to the outward in the car width direction is decreased, to also place each float 30 adjacent to each other in a car body longitudinal direction, and an extending amount of each float 30 to the car body longitudinal direction from the outrigger devices 4, 7 is decreased.