To provide a mounting structure of a gasket which suppresses the deterioration of sealing performance of a gasket.

In a mounting structure of an intake manifold 1 having a plurality of branch parts 10 and a gasket 2 having coupling parts 50 for coupling a plurality of gasket body parts 20 respectively mounted to outer peripheral sides of respective branch parts 10 to gasket body parts 20 adjacent thereto, body accommodation parts 30 for accommodating the gasket body parts 20 and coupling accommodation parts 40 for accommodating coupling parts 50 are formed in the intake manifold 1. Outside ribs 70 and inside ribs 80 are accommodated in the body accommodation parts 30. At least a groove width of a part in the coupling accommodation part 40 which is adjacent to the body accommodation part 30 is made not more than the thickness c of the gasket body part 20 including the outside rib 70 and inside rib 80. Thus, the gasket body part 20 is made hard to enter the coupling accommodation part 40 so that the deterioration of sealing performance can be suppressed.