An electrical connector includes a body and multiple conductive terminals. The body has an insertion slot. Each conductive terminal has a contact portion entering the insertion slot and a conductive portion passing downward beyond a bottom surface of the body. Each side of the insertion slot has first terminal groups and second terminal groups. The conductive portions of each first terminal group are located away from the insertion slot relative to the conductive portions of each second terminal group. The conductive portions are provided in four rows in a lateral direction. The conductive terminals include signal terminals and ground terminals. The circuit board has an adjusting hole and four rows of connecting points corresponding to the conductive portions. Each row of the connecting points include multiple signal connecting points and multiple ground connecting points. The adjusting hole is located between two signal connecting points in two adjacent rows.