To reduce swing of a pod propulsion device in a buttock flow stern of a vessel while improving propulsion efficiency.

The pod propulsion device 30 which has a propeller shaft 32 which inclines in a longitudinal direction to be in parallel with a rear up inclined ship bottom 12 and keeps water entry angles Q of a propeller 31 zero arranged in both sides of a skeg 20 provided on the rear up inclined ship bottom 12 of the buttock flow stern 10 of the vessel separating water flow into ship side flow and ship bottom flow, rectifying and providing the flow is attached on a lower surface of the buttock flow stern 10 to reduce swing of the pod propulsion device and improve propulsion efficiency.