A nitride-based compound semiconductor light-emitting element of the present invention includes: a P-type electrode; a P-type nitride-based compound semiconductor layer disposed on the P-type electrode; a light-emitting layer disposed on the P-type nitride-based compound semiconductor layer and emitting light; a nitride-based compound semiconductor layer disposed on the light-emitting layer and transmitting light emitted by the light-emitting layer therethrough; a buffer layer disposed on the nitride-based compound semiconductor layer and transmitting the light therethrough, wherein the buffer layer is made of a nitride-based compound semiconductor material and a trench is formed in the buffer layer so as to expose portions of the nitride-based compound semiconductor layer; and an N-type electrode disposed so as to cover the trench and electrically connected to the nitride-based compound semiconductor layer.