The invention relates to a Group III
nitride-based
compound semiconductor light-emitting device having a well layer, a first layer formed on one surface of the well layer, a second layer formed on the other surface of the well layer, a first region provided in the vicinity of the interface between the first layer and the well layer, and a second region provided in the vicinity of the interface between the second layer and the well layer, wherein the first and second regions are formed such that the lattice constants of the first and second
layers approach the
lattice constant of the well layer. The invention also relates to a method for producing a Group III
nitride-based
compound semiconductor light-emitting device having a light-emitting layer of a single or
multiple quantum well structure including at least an
indium (In)-containing well layer, wherein, during formation of the well layer through
vapor growth, an In source is fed through a procedure including: initiating feeding of the In source at a minimum feed rate; subsequently, elevating the In source feed rate to a target feed rate; maintaining the feed rate at the target feed rate; and subsequently, lowering the feed rate from the target feed rate to the minimum feed rate, and a Group III source other than the In source is fed at a constant feed rate from
initiation of feeding of the In source to termination of the feeding.