To start an actuator without impact by providing a multi-disc PTO clutch between a driving system for traveling and a PTO shaft and providing a friction brake for braking the PTO shaft when the PTO clutch is dissociated between a case for storing the PTO clutch and the PTO shaft.

In a small type tractor for agriculture, power of an engine is transmitted to a PTO shaft via a transmission and a PTO clutch 30 and drives various kinds of working machines. In this case, the PTO clutch 30 is constituted by integrally providing a wet type multi-disc clutch 31 and a PTO brake 41 performing release and braking by competing with transmission interruption of the clutch 31. By rotating an operating lever 55 counterclockwise by a remote control operation from a driver's seat, the PTO clutch 30 is held in a coupling state and the PTO brake 41 is held in a releasing state. By rotating the operating lever 55 clockwise, the coupling of the PTO clutch 30 is released and the PTO brake 41 is transferred to a braking state.