A multi-wavelength light-emitting device configured to emit light of a first wavelength, light of a second wavelength, and a third wavelength, includes a substrate, a first type semiconductor layer provided on the substrate, an active layer provided on the first type semiconductor layer, a second type semiconductor layer provided on the active layer, and an electrode provided on the second type semiconductor layer. The active layer includes a first active area configured to emit the light of the first wavelength, a second active area configured to emit the light of the second wavelength, and a third active area configured to emit the light of the third wavelength.