A nitride-based semiconductor light-emitting device 100 includes: a GaN substrate 10 with an m-plane surface 12; a semiconductor multilayer structure 20 provided on the m-plane surface 12 of the GaN substrate 10; and an electrode 30 provided on the semiconductor multilayer structure 20. The electrode 30 includes a Zn layer 32 and an Ag layer 34 provided on the Zn layer 32. The Zn layer 32 is in contact with a surface of a p-type semiconductor region of the semiconductor multilayer structure 20.