A connector includes a panel, a first housing assembled to the panel, and a second housing fittable to the first housing. A grommet covers the outer circumference of the second housing and has a lip to be brought into close contact with the panel. A flange is provided movably on the outer circumference of the second housing. The flange is regulated in movement with respect to the second housing with the lip away from the panel. A fitting detection mechanism enables the flange to move toward the panel and enables the lip to come in close contact with the panel, with the first housing and the second housing fitting normally together.