Abstract: A sealing structure sealing a clearance between a base (1) having a storage part (11) and a cover (2) joined to the base (1) so as to close the storage part (11) through a gasket (4) formed of a rubber-like elastic material. The base (1) and the cover (2) comprise side peripheral surfaces (12a) and (22a) opposed to each other in a direction different from a joining direction with a screw member (3). The gasket (4) is integrally fitted onto the side peripheral surface (12a) of the base (1) (or the side peripheral surface (22a) of the cover (2)), and the seal surface (41a) of the gasket is closely fitted to the side peripheral surface (22a) of the cover (2) (or the side peripheral surface (12a) of the base (1)). Thus, the outer shell of a device formed of the base (1) and the cover (2) can be easily thinned and the cover (2) can be prevented from being nonuniformly deformed by the repulsion of the gasket (4).