A connector which is capable of preventing crosstalk from occurring when a plurality of pairs of differential signal transmission contacts are arranged in a horizontal row. A housing holds a plurality of connector modules with a gap between adjacent ones thereof. Each connector module is comprised of a plate-shaped holding member, a plurality of first signal contacts held on one surface of the holding member, and a plurality of second signal contacts held on the other surface of the holding member. Positions of the respective first signal contacts of the plurality of connector modules, and positions of associated ones of the second signal contacts of the connector modules are made approximately coincident with each other in the direction of the height of the housing, respectively.