The present invention provides a group-III nitride compound semiconductor light-emitting device having high productivity and good emission characteristics, a method of manufacturing a group-III nitride compound semiconductor light-emitting device, and a lamp. A method of manufacturing a group-III nitride compound semiconductor light-emitting device includes a step of forming on a substrate 11 a semiconductor layer made of a group-III nitride compound semiconductor including Ga as a group-III element using a sputtering method. The substrate 11 and a sputtering target are arranged so as to face each other, and a gap between the substrate 11 and the sputtering target is in the range of 20 to 100 mm. In addition, when the semiconductor layer is formed by the sputtering method, a bias of more than 0.1 W/cm2 is applied to the substrate 11. Further, when the semiconductor layer is formed, nitrogen and argon are supplied into a chamber used for sputtering.