The present invention provides a nitride semiconductor light emitting device, which comprises positive and negative electrodes with high adhesion, can output high power, and does not generate heat; specifically, the present invention provides a nitride semiconductor light emitting device comprising at least an ohmic contact layer, a p-type nitride semiconductor layer, a nitride semiconductor light emitting layer, and an n-type nitride semiconductor layer, which are laminated on a plate layer, wherein a plate adhesion layer is formed between the ohmic contact layer and the plate layer, and the plate adhesion layer is made of an alloy comprising 50% by mass or greater of a same component as a main component of an alloy contained in the plate layer.