Abstract: A light emitting device includes a socket ring including a support portion and a first side wall, a light source module, and a bottom holder including a fixing portion and a second side wall. The support portion has a first surface and a second surface opposite to the first surface. The first side wall is perpendicular to the second surface. A first thread and at least one heat dissipating fin are formed on the first side wall. The first thread and the heat dissipating fin are respectively located on an inner surface and an outer surface of the first side wall. The second side wall stands erect on the fixing portion, and has a second thread coupled to the first thread.