A method of designing a light-emitting device incorporating a light-emitting element, characterized by comprising: configuring a light emitted from the light-emitting device so as to include, in a main radiant direction thereof, light whose distance D uvSSL from a black-body radiation locus as defined by ANSI C78.377 satisfies -0.04268 ≤ D uvSSL ≤-0.0070, and if a spectral power distribution of light emitted from the light-emitting device in the radiant direction is denoted by φ SSL (λ), a spectral power distribution of a reference light that is selected according to T SSL of the light emitted from the light-emitting device in the radiant direction is denoted by φ ref (λ), tristimulus values of the light emitted from the light-emitting device in the radiant direction are denoted by (X SSL, Y SSL, Z SSL), and tristimulus values of the reference light that is selected according to T SSL of the light emitted from the light-emitting device in the radiant direction are denoted by (X ref, Y ref, Z ref), and if a normalized spectral power distribution S SSL (λ) of light emitted from the light-emitting device in the radiant direction, a normalized spectral power distribution S ref (λ) of a reference light that is selected according to T SSL of the light emitted from the light-emitting device in the radiant direction, and a difference ΔS (λ) between these normalized spectral power distributions are respectively defined as S SSL λ = φ SSL λ / Y SSL, S ref λ = φ ref λ / Y ref and Δ S λ = S ref λ − S SSL λ and if a wavelength that produces a longest wavelength local maximum value of S SSL (λ) in a wavelength range from 380 nm to 780 nm is denoted by λ R (nm), then determining a wavelength A4 that satisfies S SSL (Λ4)= S SSL (λ R)/2 and exists on a longer wavelength-side of λ R, calculating an index A cg according to the formula below, wherein the index A cg satisfies -461 ≤ A cg ≤ -25, A cg = ∫ 380 495 Δ S λ d λ + ∫ 495 590 − Δ S λ d λ + ∫ 590 Λ 4 Δ S λ d λ. configuring a light emitted from the light-emitting device so as to include, in a main radiant direction thereof, light whose distance D uvSSL from a black-body radiation locus as defined by ANSI C78.377 satisfies -0.04268 ≤ D uvSSL ≤-0.0070, and if a spectral power distribution of light emitted from the light-emitting device in the radiant direction is denoted by φ SSL (λ), a spectral power distribution of a reference light that is selected according to T SSL of the light emitted from the light-emitting device in the radiant direction is denoted by φ ref (λ), tristimulus values of the light emitted from the light-emitting device in the radiant direction are denoted by (X SSL, Y SSL, Z SSL), and tristimulus values of the reference light that is selected according to T SSL of the light emitted from the light-emitting device in the radiant direction are denoted by (X ref, Y ref, Z ref), and if a normalized spectral power distribution S SSL (λ) of light emitted from the light-emitting device in the radiant direction, a normalized spectral power distribution S ref (λ) of a reference light that is selected according to T SSL of the light emitted from the light-emitting device in the radiant direction, and a difference ΔS (λ) between these normalized spectral power distributions are respectively defined as S SSL λ = φ SSL λ / Y SSL, S ref λ = φ ref λ / Y ref and Δ S λ = S ref λ − S SSL λ and if a wavelength that produces a longest wavelength local maximum value of S SSL (λ) in a wavelength range from 380 nm to 780 nm is denoted by λ R (nm), then determining a wavelength A4 that satisfies S SSL (Λ4)= S SSL (λ R)/2 and exists on a longer wavelength-side of λ R, calculating an index A cg according to the formula below, wherein the index A cg satisfies -461 ≤ A cg ≤ -25, A cg = ∫ 380 495 Δ S λ d λ + ∫ 495 590 − Δ S λ d λ + ∫ 590 Λ 4 Δ S λ d λ.