A connector includes a pair of housings to be fitted to each other by inserting an insertion part of one housing into a tubular part of another housing. On an outer peripheral surface of the insertion part of the one housing, a plurality of outer ribs which project from the outer peripheral surface are provided separately in a circumferential direction to extend from a front end of the insertion part to a rear side. On an inner peripheral surface of the tubular part of the other housing, a plurality of inner ribs which project from the inner peripheral surface are provided separately in a circumferential direction to extend from a front end of the tubular part to a rear side. The outer ribs and the inner ribs are provided such that positions in the circumferential direction are deviated from each other.