To enhance easiness of getting on/off a working vehicle by preventing a filling auxiliary frame from unexpectedly turning during getting on/off, in making the filling auxiliary frame function as a getting on/off grip.

This tractor, turning the filling auxiliary frame 10 into a horizontal posture and a vertical posture, in making the filling auxiliary frame 10 permitting a fuel supply tank to be placed function as the getting on/off grip, includes a posture holding mechanism for holding the filling auxiliary frame 10 in respective postures. The posture holding mechanism releases posture holding of the filling auxiliary frame 10 by pressing the filling auxiliary frame 10 toward the internal tractor body along its rotational center line.