PURPOSE: To prevent irregular revolution and to stabilize controllability by linking steering handle operation to revolving speed of front wheel, changing the revolving speed and controlling the change of revolving speed based on a steering angle so as to make revolving speed of front wheel during rotation higher than that of rear wheel.

CONSTITUTION: In a sulky transplanter of driving front and rear wheels 6 and 8, a speed change member such as speed change cylinder 56 or a speed change motor 103 to vary revolving speed of the front wheel 6 by linking a steering handle 14 operation to the revolving speed of the front wheel is equipped, the speed change members 56 and 103 are constituted in such a way that the speed change members are automatically controlled based on a stirring angle so as to make the revolving speed of the front wheel 6 during rotation higher than that of the rear wheel. Consequently, travel speed of the front wheel 6 in change of course at butt is made higher than that of the rear wheel 8 so that sliding force is prevented from acting on the front wheel 6 even on readily slidable muddy surface, irregular revolution, etc., are easily suppressed and controllability and stability are improved.