A damper has silicone-based unvulcanized rubber interposed between a housing and a shaft which are disposed in such a manner as to be relatively rotatable about an axis in directions with respect to each other, and rotational energy between the housing and the shaft is absorbed through the deformation of the silicone-based unvulcanized rubber. The size of the cavity and the size of the proof mass exceed the corresponding overall dimensions of the elastic element. A current mirror circuit comprises a third and fourth transistor and is connected to the zero-volt clamp circuit for causing a current of the same value as that of a current flowing in the zero-volt clamp circuit to flow.