A tiller (10) includes: a rotary tilling operation section (15) whose upper portion covered with a fender (17) an auxiliary wheel (50) provided in front of the rotary tilling operation section (15) and a pivot arm (40) vertically pivotably mounted on a machine body (12) for adjusting a height of the auxiliary wheel. The pivot arm (40) includes a lever (60) operable in a vertical direction by a human operator holding a grip (64) when a pivotal angle of the pivot arm is to be adjusted. The grip (64) is provided on the lever in such a manner that the grip is located higher than the auxiliary wheel (50) when the pivot arm (40) is located at its lowest pivotal position, and the grip (64) is located immediately above the fender (17) at least when the pivot arm is located at its highest pivotal position.
