An LED bulb includes an LED module having a PCB on which at least one LED element is mounted. A housing has a plurality of heat dissipating protrusions which protrude from an outer circumferential surface thereof, with a thread being formed on a predetermined portion of the housing. A light transmitting cover has a thread by which the cover can be fastened to the thread which is formed on the predetermined portion of the housing, in a threaded manner. Further, the LED bulb includes a bottom case into which an inverter for supplying a direct current to the LED module is inserted. The bottom case is inserted into the housing to be fastened to the housing. A socket is fastened to the bottom case.