A connector comprising: 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 , wherein 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 wherein 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 wherein the plurality of outer ribs are provided, on the outer peripheral surface of the insertion part , at a center portion of a lower portion in a width direction, a portion closer to one side of the width direction than a center portion of the upper portion in the width direction, and a portion closer to the other side of the width direction than the center portion of the upper portion, wherein the plurality of inner ribs are provided, on the inner peripheral surface of the tubular part , at a center portion of a lower portion in a width direction, a portion closer to one side of the width direction than a center portion of the upper portion in the width direction, and a portion closer to the other side of the width direction than the center portion of the upper portion, characterized in that the plurality of outer ribs extend from a front end of the insertion part to a rear side, the plurality of inner ribs extend from a front end of the tubular part to a rear side, in a state in which the pair of housings are fitted, the plurality of outer ribs and the corresponding inner ribs are arranged adjacently in the circumferential direction but separated from each other. 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 , wherein 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 wherein 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 wherein the plurality of outer ribs are provided, on the outer peripheral surface of the insertion part , at a center portion of a lower portion in a width direction, a portion closer to one side of the width direction than a center portion of the upper portion in the width direction, and a portion closer to the other side of the width direction than the center portion of the upper portion, wherein the plurality of inner ribs are provided, on the inner peripheral surface of the tubular part , at a center portion of a lower portion in a width direction, a portion closer to one side of the width direction than a center portion of the upper portion in the width direction, and a portion closer to the other side of the width direction than the center portion of the upper portion, characterized in that the plurality of outer ribs extend from a front end of the insertion part to a rear side, the plurality of inner ribs extend from a front end of the tubular part to a rear side, in a state in which the pair of housings are fitted, the plurality of outer ribs and the corresponding inner ribs are arranged adjacently in the circumferential direction but separated from each other. <EOS>