Abstract: The structure of a lamp socket unit has a lamp bulb, a lamp base and a lamp holder; said lamp bulb comprising vacuum part within in it providing a filament, a rear end and a pair of conductor wires; said lamp base comprising a lug, a neck and an end, said end having two holes, said lug having an opening end, the conductor wires passed through said opening end to enter holes, and said wires to be bent along the outside of said end so that the end of said lamp bulb received within the opening end of said lamp base; said lamp holder being hollow in it, both are opening end, the terminal to be contacted by the conductor wire passing through the rear opening of the lamp holder; the front opening received the end and neck of the lamp base, to cause the conductor wires to be contacted to the terminals so as to complete the electrical circuit; wherein the lug and neck of lamp base having one or more than one elasticity or expandable part, the outside diameter of neck of the lamp base is larger than the inside diamete