An electrical connector includes an insulated seat, and first and second seats. A plurality of first and second terminals are embedded partially into the first and second seats via insert molding process in such a manner that when the first and second seats are assembled to the insulated seat, a first engagement structure of the first seat engages with a second engagement structure of the second seat while one of the two clamping structures at the insulated seat clamps an assembly of the first and second assembling structures of the first and second seats.