An electrical connector includes an insulating body, a low-speed transmission terminal group including electrical terminals, a high-speed transmission terminal group including at least one outputting signal terminal and at least one receiving signal terminal, and a positioning body which has a fastening portion mounted under a rear of the insulating body and a positioning portion hanged behind the insulating body. Each of the terminals has a fastening strip, a contact portion and a soldering tail connected with two opposite ends of the fastening strip. The soldering tails of the outputting and receiving signal terminals protrude sideward to form eave boards broadening the outputting and receiving signal terminals for lowering the differential impedance of the high-speed transmission terminal group. The fastening strips are disposed in two opposite surfaces of the insulating body. The soldering tails and the eave boards stretch behind the insulating body to be positioned in the positioning portion.