PROBLEM TO BE SOLVED: To effectively prevent or reduce the occurrence of a region having no leveling operation due to a rear cover of the rotary tiller though being tilled by a rotary tiller, in the execution of lifting/lowering interlocked control.SOLUTION: A controller executes the closure control for transferring a PTO clutch unit in a power cut-off state while holding the rotary tiller in a working position, upon receiving a lifting command of the rotary tiller when the PTO clutch unit is brought into a transmitted state and a rotary tiller is positioned in the working position in a selection state of a lifting/lowering interlocked mode, and executes the lifting control of a lifting/lowering actuator so that the rotary tiller may be positioned in a non-working position after the execution of the closure control.
