Gasket

A gasket comprising an elastic part containing a rubber having a dynamic spring constant of 1.5 g/μm or lower as measured under conditions of 23±2° C., 100 Hz, and a strain amplitude of 0.1% according to JIS K6394:2007, wherein the rubber is nitrile rubber with a nitrile content of 33% or less,

• the rubber further contains at least one carbon black selected from SRF carbon black and MT carbon black,
• when the rubber contains SRF carbon black, the content of SRF carbon black is 56 parts by mass or less relative to 100 parts by mass of the rubber, and when the rubber contains MT carbon black, the content of MT carbon black is 45 parts by mass or more relative to 100 parts by mass of the rubber.