To provide a device for opening and closing the seat and lid of a toilet stool, such that large torque can be obtained even though the device is small and that it is easy to match the toilet seat and lid can with rotary moment in details and accentuate their action.

A first rotating shaft 3 is freely rotationally mounted on a case main body 19 designed to be mounted on a toilet stool main body 1, a first rotation control means 8 comprising a cam mechanism which is under the action of an elastic means is provided on one side of the first rotating shaft enclosed in the case main body, second rotation control means 21 comprising rotary dampers are provided in two parallel stages inside the case main body and above or below the first rotation control means, a driving force transmission means 13 is provided between the first and second rotation control means, the mounting shaft of either a toilet seat or a toilet lid is freely rotationally borne on the rotating shaft, and the other is fixed in place in such a way as to rotate together with the rotating shaft.