Referring to FIG. 1, FIG. 1 illustrates a prior electrical connector, such as a Taiwan utility model patent publication No. M276350 (Application No. 094205123), which discloses a first shell 11, a second shell 12, and a terminal base 13. The terminal base 13 is provided with a plurality of terminals 14 and is covered in the first shell 11, the first shell 11 is provided with catching portions 111 respectively at two side walls thereof, and the second shell 12 is provided with latching portions 121 respectively at two side walls thereof. The latching portions 121 may be respectively correspondingly engaged with the catching portions 111 so that the second shell 12 may be fixed outside the first shell 11, and the second shell 12 is provided with connecting legs 122 respectively at left and right sides thereof, connecting legs 122 may be disposed to respectively pass through through-holes of a circuit board (not shown), so that the electrical connector may be fixedly soldered on the circuit board.
However, the first shell and the second shell of the electrical connector are assembled by a latching mode, and thus are not firmly fixed therebetween. Therefore, the first shell and the second shell are relatively shifted due to shock yielded from an external force (for example, if conveyed by a conveyer belt) during soldering the electrical connector to the circuit board. Accordingly, a through-hole type design must be adopted for the connecting legs of the second shell. If a Surface Mount Technology (SMT)-TYPE is alternatively used, it is easy to cause that the SMT-TYPE connecting legs of the second shell and the SMT-TYPE soldering portions of the terminals are not coplanar, and a problem of missing solder for the terminals of the electrical connector is possible, with the potential result that signal transmission will be poor. Secondly, also because the first shell and the second shell are assembled by the latching mode and not firmly fixed therebetween, there is a gap between the first shell and the second shell, so that most stress during inserting or withdrawing a mating counterpart connector is still born by the first shell when the mating counterpart connector is inserted into or withdrawn from the electrical connector, and in turn will be born by the soldering portions of the terminals, thereby easily making the electrical connector to be released, that is to say, there is a phenomenon that the terminals will be released. On the other hand, because the circuit board belongs to a multilayer-sheet structure design, the number of the through-holes would influence on a wiring layout inside the circuit board. As a result, the connecting legs of the second shell disposed to respectively pass through the through-holes of the circuit board may make a problem on the wring layout design for the circuit board serious, and may result in increased cost. Consequentially, certain individuals would appreciate an improved connector.