Spectral broadening of blue apatite phosphors (Sr, Ba)₅(PO₄)₃Cl:Ce³⁺ was achieved by changing Sr-Ba cation combinations. Their blue emission colors come from the 5d¹‑4f¹ transition of Ce³⁺ ions, and their excitation bands are ranged from 250 nm to 400 nm. The substitution of Ba²⁺ for Sr²⁺ ions was confirmed by Raman spectra. The broadest Raman width in Sr_2.45Ba_2.45(PO₄)₃Cl:Ce³⁺ phosphor supported its highest disorder of the host lattice, leading to the emission spectral broadening with a half width of 95.5 nm due to the larger variation in crystal filed strength. The thermal quenching behavior showed the blue emission maintenance of 80 % around 100°C. Finally, the 400 nm-pumped white-LED was optically simulated so as to achieve an excellent color‑rendering index (Ra) of 90 at white color point.