To provide an outrigger device of a working vehicle capable of preventing forgetting of locking of an outrigger member taking a storage attitude and forgetting of release of the locking.

A lock means includes: a movable lock member 41 to be driven by a lock cylinder 44; a lock part 42 provided in the outrigger member 16 to lock the outrigger member 16 by the movable lock member 41 located at a lock position in a state of the outrigger member 16 taking the storage attitude; a controller 29; and a second hydraulic pump 32, a selector valve 36 and a driving pipeline 48 as means for holding the movable lock member 41 at a release position against a spring 47 in a bottom chamber by supplying discharge oil to a rod chamber 44b of the lock cylinder 44 during an input of a command signal from a grounding command switch 37 commanding grounding of the outrigger member 16 to the controller 29 and during an input of a command signal from a storage command switch 38 commanding storage of the outrigger member 16 to the controller 29.