GASKET

A gasket is sandwiched between a cylinder head (1) and a cylinder block (2) and shares, with the cylinder block (2), a combustion chamber hole (30) extending in a hole axis direction. The gasket (3) includes a first plate portion (100), a second plate portion (110), an intermediate plate portion (120), and a shim (130). The first plate portion (100) abuts against the cylinder head (1) and has a substantially constant plate thickness. The second plate portion (110) abuts against the cylinder block (2) and has a substantially constant plate thickness. The intermediate plate portion (120) is sandwiched between the first plate portion (100) and the second plate portion (110) and has a substantially constant plate thickness. The shim (130) is sandwiched between the first plate portion (100) and the intermediate plate portion (120) and is disposed over an entire periphery of a peripheral edge (30e) of the combustion chamber hole (30). The shim (130) includes a gradually changing portion (131). The gradually changing portion (131) has a thickness in the hole axis direction that becomes thicker with a separation from the peripheral edge (30e) of the combustion chamber hole (30).