PURPOSE: To easily control the rate of transmission of energy, by fitting an axial member into a cylinder member while providing a labyrinth in a connection surface of the fitted members and increasing a pressure of fluid by the pumping action in the labyrinth part thus transmitting a turning effect.

CONSTITUTION: An axial member 1 is rotatably and slidably fitted into a cylinder member 2, while a labyrinth 10 is provided between the peripheral surface of the axial member 1 and the internal peripheral surface of the cylinder member 2, and a device enables a turning effect to be transmitted to the cylinder member 2 from the axial member 1 in the driving side through fluid in a part of the labyrinth 10. In this way, the rate of transmission can be adjusted by changing a length in the axial direction of the labyrinth 10 or a fluid level in the part of the labyrinth 10 further by providing an optional pressure difference between an inflow port 5 and an outflow port 6. Accordingly, the rate of transmission of energy can be easily further accurately controlled.