There are provided a method of manufacturing a nitride semiconductor light emitting device and the nitride semiconductor light emitting device manufactured by the method, the method including: forming a light emitting structure by sequentially growing a first conductivity nitride layer, an active layer and a second conductivity type nitride layer on a preliminary substrate for nitride single crystal growth; separating the light emitting structure in accordance with a size of final light emitting device; forming a conductive substrate on the light emitting structure; polishing a bottom surface of the preliminary substrate to reduce a thickness of the preliminary substrate; forming uneven surface structures by machining the preliminary substrate; selectively removing the preliminary substrate to expose portions of the first conductivity type nitride layer; and forming electrodes on the portions of the first conductivity type nitride layer exposed by selectively removing the preliminary substrate.