A gasket held between opposite flange joint surfaces with a bolt includes a combination of a complex material with a rubber material formed on one or both sides of a steel plate, the complex material having a convex or waveform bead, and a circular metal plate arranged at a bolt portion with a through-hole where a shank of the bolt penetrates and a bearing corresponding portion that corresponds to a bearing of the bolt around the through-hole. The gasket is configured to have the thickness (H3) of the bead provided to the complex material greater than the thickness (H2) of the circular metal plate that is equal to or greater than the thickness (H1) of the complex material. This structure provides a gasket indicating good sealing properties under such circumstances that a flange has low stiffness, a tightening load is reduced, and the distance between bolts is expanded.