A helicopter, the helicopter comprising: a hollow power transmitting shaft including an ejection hole through which an internal space of the power transmitting shaft communicates with an outside of the power transmitting shaft; bearings supporting the power transmitting shaft such that the power transmitting shaft is rotatable; a main lubricating circuit including a main tank in which lubricating oil is stored, a main nozzle having a nozzle hole through which the lubricating oil supplied from the main tank is discharged to the internal space of the power transmitting shaft, and a hydraulic pump configured to supply the lubricating oil by pressure from the main tank to the main nozzle; and an auxiliary lubricating circuit including an auxiliary tank in which lubricating oil is stored and an auxiliary nozzle arranged lower than the auxiliary tank at the outside of the power transmitting shaft, characterized in that: the power transmitting shaft is arranged in such a posture as to be inclined relative to a horizontal direction and a vertical direction; the auxiliary nozzle is arranged higher than the bearings; and the auxiliary nozzle is configured to drop the lubricating oil supplied from the auxiliary tank by the own weight of the lubricating oil, to an uppermost one of the bearings from above so that the lubricating oil which has dropped from the auxiliary nozzle serially lubricates the bearings in order. a hollow power transmitting shaft including an ejection hole through which an internal space of the power transmitting shaft communicates with an outside of the power transmitting shaft; bearings supporting the power transmitting shaft such that the power transmitting shaft is rotatable; a main lubricating circuit including a main tank in which lubricating oil is stored, a main nozzle having a nozzle hole through which the lubricating oil supplied from the main tank is discharged to the internal space of the power transmitting shaft, and a hydraulic pump configured to supply the lubricating oil by pressure from the main tank to the main nozzle; and a main tank in which lubricating oil is stored, a main nozzle having a nozzle hole through which the lubricating oil supplied from the main tank is discharged to the internal space of the power transmitting shaft, and a hydraulic pump configured to supply the lubricating oil by pressure from the main tank to the main nozzle; and an auxiliary lubricating circuit including an auxiliary tank in which lubricating oil is stored and an auxiliary nozzle arranged lower than the auxiliary tank at the outside of the power transmitting shaft, an auxiliary tank in which lubricating oil is stored and an auxiliary nozzle arranged lower than the auxiliary tank at the outside of the power transmitting shaft, characterized in that: the power transmitting shaft is arranged in such a posture as to be inclined relative to a horizontal direction and a vertical direction; the auxiliary nozzle is arranged higher than the bearings; and the auxiliary nozzle is configured to drop the lubricating oil supplied from the auxiliary tank by the own weight of the lubricating oil, to an uppermost one of the bearings from above so that the lubricating oil which has dropped from the auxiliary nozzle serially lubricates the bearings in order. the power transmitting shaft is arranged in such a posture as to be inclined relative to a horizontal direction and a vertical direction; the auxiliary nozzle is arranged higher than the bearings; and the auxiliary nozzle is configured to drop the lubricating oil supplied from the auxiliary tank by the own weight of the lubricating oil, to an uppermost one of the bearings from above so that the lubricating oil which has dropped from the auxiliary nozzle serially lubricates the bearings in order.