A bulb assembly includes a shell, a holder, and a bulb, wherein the bulb and the holder are received in the shell, wherein the bulb has two conductive wires passing through the holder and being folded upward outsides. The shell is provided with a central plate extending to the bottom of the holder and separating two conductive wires from each other. Hence, there are two connecting types for electrical wires with conductive pins to insert into shell and contact with various position of the conductive wires that facilitates the utilization of the products.