Generally, existing LED lamps often use robust metallic cases since each of the cases functions as a heat sink. Various shapes for increasing the heat dissipation properties of the case have been employed; there is no unified shape. Existing LED lamps therefore have a problem that they cannot be easily disassembled at the time of recycling. Thus, an object is to provide a lamp which can be easily disassembled at the time of recycling. A lamp includes: a case having a certain shape; an LED module including a semiconductor light-emitting device; and a power supply circuit provided inside the case, for driving the semiconductor light-emitting device to emit light, wherein on an outer side of the case, a step for splitting the case is formed.