A safety valve includes a body having a flow passage formed therein, the flow passage including an inlet an outlet, in which a valve seat is formed around the inlet or the outlet, a disc provided in the body, in which one side of the disc is in contact with the valve seat, an elastic member that is connected to an opposite side of the disc and that elastically supports the disc and has a set elasticity, and a sealing member made of polyimide that is provided on contact surfaces of the disc and the valve seat.