A sealing device to be installed in an exhaust gas recirculation device that recirculates a portion of exhaust gas to intake air, wherein the sealing device is configured to seal an annular gap between a rotary shaft and a housing having a shaft hole for the rotary shaft, the rotary shaft rotating a valve body of a control valve that controls an amount of exhaust gas to be recirculated, and the sealing device comprises: a metal ring including a cylindrical section and an inward flange section disposed at one end of the cylindrical section, the cylindrical section being configured to be fitted to an inner circumference surface defining the shaft hole in a close contact state with the inner circumference surface; a resin seal including a plate-shaped annular resin member, an outer circumference side of the resin seal being fixed to the metal ring and an inner circumference side of the resin seal being configured to be in close contact with and slide on an outer circumference surface of the rotary shaft in a state deformed to curve toward a sealing target region; and a flat spring including a plate-shaped annular metal member, an outer circumference side of the flat spring being fixed to the metal ring and an inner circumference side of the flat spring being configured to deform to curve along the resin seal and press the inner circumference side of the resin seal radially inward; characterized by further comprising a metal slide bearing sandwiched between the resin seal and the inward flange section, the metal slide bearing being configured to slide on the outer circumference surface of the rotary shaft and to limit the eccentricity of the rotary shaft, wherein an outer circumference edge of the resin seal is compressed between an outer circumference edge of the flat spring and the slide bearing. the sealing device is configured to seal an annular gap between a rotary shaft and a housing having a shaft hole for the rotary shaft, the rotary shaft rotating a valve body of a control valve that controls an amount of exhaust gas to be recirculated, and the sealing device comprises: a metal ring including a cylindrical section and an inward flange section disposed at one end of the cylindrical section, the cylindrical section being configured to be fitted to an inner circumference surface defining the shaft hole in a close contact state with the inner circumference surface; a resin seal including a plate-shaped annular resin member, an outer circumference side of the resin seal being fixed to the metal ring and an inner circumference side of the resin seal being configured to be in close contact with and slide on an outer circumference surface of the rotary shaft in a state deformed to curve toward a sealing target region; and a flat spring including a plate-shaped annular metal member, an outer circumference side of the flat spring being fixed to the metal ring and an inner circumference side of the flat spring being configured to deform to curve along the resin seal and press the inner circumference side of the resin seal radially inward; characterized by further comprising a metal slide bearing sandwiched between the resin seal and the inward flange section, the metal slide bearing being configured to slide on the outer circumference surface of the rotary shaft and to limit the eccentricity of the rotary shaft, wherein an outer circumference edge of the resin seal is compressed between an outer circumference edge of the flat spring and the slide bearing. a metal ring including a cylindrical section and an inward flange section disposed at one end of the cylindrical section, the cylindrical section being configured to be fitted to an inner circumference surface defining the shaft hole in a close contact state with the inner circumference surface; a resin seal including a plate-shaped annular resin member, an outer circumference side of the resin seal being fixed to the metal ring and an inner circumference side of the resin seal being configured to be in close contact with and slide on an outer circumference surface of the rotary shaft in a state deformed to curve toward a sealing target region; and a flat spring including a plate-shaped annular metal member, an outer circumference side of the flat spring being fixed to the metal ring and an inner circumference side of the flat spring being configured to deform to curve along the resin seal and press the inner circumference side of the resin seal radially inward; characterized by further comprising a metal slide bearing sandwiched between the resin seal and the inward flange section, the metal slide bearing being configured to slide on the outer circumference surface of the rotary shaft and to limit the eccentricity of the rotary shaft, wherein an outer circumference edge of the resin seal is compressed between an outer circumference edge of the flat spring and the slide bearing.