A lamp cap can include: a metal shell; an insulating base disposed on the metal shell; an elastic connecting mechanism disposed on the insulating base, wherein the elastic connecting mechanism can include a first metal element connected to the insulating base, a second metal element disposed opposite to the first metal element, and a spring disposed between the first metal element and the second metal element and configured for supporting the second metal element and electrically communicating the first metal element and the second metal element, a main part of the second metal element can extend into the metal shell, when the main part of the second metal element is pressed by a threaded portion of a bulb, the spring can be compressed and the second metal element is movable relative to the insulating base.