Rotary device having a sealing structure

A seal member is configured so that an annular rubber member is disposed in an annular storage chamber of a resin annular member. Thus, the rubber annular member is not directly in contact with a drive shaft, and the rubber annular member can be prevented from wearing or peeling without requiring a rotation stopping structure for the seal member. Furthermore, the seal member is provided with first and second communication mouths, so that a brake fluid pressure is applied to compartments obtained by dividing the annular storage chamber using the rubber annular member. Thus, the rubber annular member is pressed, and then is elastically deformed, and accordingly, the resin annular member is expanded by the elastic force. Thus, a self-sealing operation can be performed on the basis of a high pressing force.