To provide a gasket capable of reducing the manufacturing cost.

The gasket 30 has a male screw piece with a fluid channel and a male screw and a female piece with a fluid channel and a female screw, and is used for a joint to connect the two channels by screwing the male screw piece to the female screw piece. The gasket 30 also has an annular gasket body 31 and a presser member 32 slackly engaged with the outer periphery of the gasket body 31. The presser member 32 has an annular band part 321 disposed along the outer periphery of the gasket body 31 with a notch in the middle and clasping pieces 322 facing each other in the cross direction of the band part 321 for clasping both end faces of the gasket body 31. The band part 321 is made of an elastic material and can be expanded/contracted in the radial direction of the gasket body 31.