An electrical connector 1 contains a plurality of contacts 31, a first ground plate 32L and a second ground plate 32R facing the plurality of contacts 31 and arranged so as to be separated from each other in a ground plane parallel to the at least one plane in which the plurality of contacts 31 are arranged and an insulator 33 for holding the plurality of contacts 31, the first ground plate 32L and the second ground plate 32R in a state that the plurality of contacts 31, the first ground plate 32L and the second ground plate 32R are insulated from each other. Both of the first ground plate 32L and the second ground plate 32R include an extending portion extending from one of the first ground plate 32L and the second ground plate 32R toward the other one of the first ground plate 32L and the second ground plate 32R in the ground plane.