To smoothly flow a lubricating oil, even when rotating air current is generated within a passage of the lubricating oil by a rotating operation of a shaft by providing a flow suppressing member for suppressing flow of a peripheral direction of the lubricating oil flowing in the passage.

A flow suppressing member 25 is formed by being extended in the radial direction and in the shaft direction of a PTO shaft 12 so as to make a dam of a prescribed height on an inner wall surface 15a at a corner on the inside of a recessed part of a housing part 15b. A lubricating oil OL smoothly flows without a stay because flow of the peripheral direction of the lubricating oil OL is suppressed by the flow suppressing member 25, even if a rotating air current is generated in the lubricating oil OL within a passage 16 by a rotating operation of the PTO shaft 12. Thus, a stay of the lubricating oil OL is prevented and a stable operation is realized. Because the flow suppressing member 25 is disposed on an inner wall surface 15a of a housing 15b with a difference in level, generation of a stay in the difference in level portion where the lubricating oil OL is easy to stay is surely suppressed because flow velocity is easy to be changed.