A connector includes a connecter housing and a case. A housing fixing portion of the case includes a first rib which extends in a circumferential direction of the housing fixing portion. The connector housing includes a second rib which extends in a circumferential direction. An inner circumferential groove which extends in the circumferential direction is formed on an inner circumferential face of the first rib. Vertical protrusions which extend in an inserting direction of the second rib into the inner circumferential groove are formed at a plurality of positions on at least one of vertical side walls defining the inner circumferential groove. Top parts of the vertical protrusions are deformed so as to engage the second rib with the inner circumferential groove when the second rib is inserted into the inner circumferential groove.