An electrical connector having two vertically movable bases to enhance overall levelness of pins. The electrical connector includes a bottom base, a positioning structure, and a top base covering over the bottom base. The bottom base includes a mother base and a daughter base, wherein the mother base is formed with an opening, the daughter base is contained in the opening, one row of terminals is arranged on the daughter base, and each of the terminals has an elastic contact and a pin. The positioning structure is formed on the mother base and the daughter base to make the daughter base vertically movable and to horizontally restrict the daughter base in the opening of the mother base.