An epitaxial wafer for an AlGaInP light-emitting device includes a p-type GaAs substrate, a reflection layer in the form of a laminated body of multiple semiconductor layers provided over the substrate, a double hetero-junction light-emitting structure of AlGaInP formed over the reflection layer, the light-emitting structure including an active layer between upper and lower cladding layers, and a current diffusion layer of AlGaAs provided over the double hetero-junction light-emitting structure. The current diffusion layer is transparent to light emitted by the light-emitting structure. The current diffusion layer is n-type AlGaAs, and has a carrier concentration of from 10.sup.17 cm.sup.-3 to 2.times.10.sup.19 cm.sup.-3, and a thickness that is not more than 1 .mu.m.