Abstract: A high performance sealing device (1) having an excellent pressure resistance, usable at a working pressure of 0 to 2 MPa, and not damaged even if the pressure of high-pressure fuel of 5 MPa or higher is applied thereto, wherein high pressure fuel on the high pressure side (H) is sealed by a first seal part (2), oil from a cam side on a low pressure side (L) is sealed by a second seal part (3), and the fuel slightly leaked through the first seal part (2) is sealed by the second seal part (3) to form a double seal structure, and a resin ring (21) slidably and sealingly coming into contact with a shaft (10) is used in the first seal part (2), whereby abnormal wear does not occur even if fuel with poor lubrication is used, and the durability of the seal is increased.