A light emitting device with a top electrode and a bottom electrode is pushed by a plug to make contacts with either an upper metal plate or a lower metal plate each serving as one of the leads for an electrode of the light emitting devices. The plug is inserted through an opening larger than the light emitting device in the metal plate not in contact with the light emitting device but serving as another lead for the light emitting device. The plug is locked in place by means of threaded screw heads, snug-fit, snap-on buttons or an elastic sleeve. Thus, the light emitting device can be easily replaced without any wire bonding. A plurality of the light unit can be sandwiched between the upper metal plate and the lower metal plate.