A rice planting machine comprises: an actuator for changing the speed of the engine and/or the transmission ratio of the HST a speed change means serving as the operation device for changing the amount of drive of the actuator a control device connected to both the actuator and the speed change means and changing the speed of the vehicle by changing either the speed of the engine and/or the transmission ratio of the HST by means of the actuator on the basis of the amount of operation of the speed change means and a maximum speed setting means connected to the control device and serving as the operation device for changing the maximum speed which is the speed of the vehicle when the speed change means is operated the maximum amount.
