A sealing apparatus is provided. The sealing apparatus is arranged between two members facing each other for sealing a space between the two members. The sealing apparatus comprises a sealing body in contact with the space, in which the sealing body has a tensile strength of 10 MPa or more measured in accordance with the provisions of JIS K 6251: 2017, an elongation at break of 200% or more measured in accordance with the provisions of JIS K 6251: 2017, a TR10 temperature of 40 C. or lower in a low-temperature elastic recovery test, measured in accordance with the provisions of JIS K 6261-4: 2017, and a compression set at 100 C. with an elapsed time of 70 hours in a shape of a G25 O-ring as described in the provisions of JIS B 2401-1: 2012, measured in accordance with the provisions of JIS K 6262: 2013, of 40% or less.

To provide a sealing resin composition and a seal that are capable of being used, in particular, in high temperature and high pressure gas, in particular hydrogen gas. A sealing resin composition is used in a piston ring 1 for sealing gas. When a molded body of the sealing resin composition is exposed to gas with a pressure of 82 MPa and a temperature of 200 C. for 192 hours, a dimensional change rate of the molded body relative to the molded body before the exposure is +1.0% or less, a retention rate of the tensile strength of the molded body after the exposure is 80% or more as the tensile strength of the molded body before the exposure is defined as 100%. The tensile strength of the molded body of the sealing resin composition is 100 MPa or more by a measuring method based on ASTM D638.