A nitride based light emitting device is disclosed. More particularly, a nitride based light emitting device capable of improving light emitting efficiency and reliability thereof is disclosed. The nitride based light emitting device includes a first conductive semiconductor layer connected to a first electrode, a second conductive semiconductor layer connected to a second electrode, an active layer located between the first conductive semiconductor layer and the second conductive semiconductor layer and having a quantum well structure, a first insertion layer located in at least one of a boundary between the first conductive semiconductor layer and the active layer and a boundary between the second conductive semiconductor layer and the active layer, and a second insertion layer located adjacent to the first insertion.