According to one embodiment, there is provided a white light source system. P(λ), B(λ) and V(λ) satisfy an equation (1) below in a wavelength range of 380 nm to 780 nm. The white light source system satisfies an expression (2) below in a wavelength range of 400 nm to 495 nm: ∫ 380 780 ⁢ P ⁡ ( λ ) ⁢ V ⁡ ( λ ) ⁢ d ⁢ ⁢ λ = ∫ 380 780 ⁢ B ⁡ ( λ ) ⁢ V ⁡ ( λ ) ⁢ d ⁢ ⁢ λ ( 1 ) P ⁡ ( λ ) / B ⁡ ( λ ) ≦ 1.8 . ( 2 ) where P(λ) is a light emission spectrum of white light, B(λ) is a light emission spectrum of blackbody radiation of a color temperature correspond to a color temperature of the white light, and V(λ) is a spectrum of a spectral luminous efficiency.