A green emitting phosphor is provided, allowing the internal quantum efficiency to be increased. The green emitting phosphor comprises a mother crystal containing Sr, Ga and S, and a luminescent center, characterized in that, in an XRD pattern, the ratio of the diffraction intensity of the maximum peak appearing at diffraction angle 2θ=14 to 20° over the diffraction intensity of the maximum peak appearing at diffraction angle 2θ=21 to 27° is 0.4 or greater.