Red light-emitting phosphor and light-emitting device

(1-x)(1-x-y)y2x28A red light-emitting phosphor capable of emitting red light upon excitation with light having a wavelength of 350 to 420 nm, represented by the following compositional formula (1): AEuLnDMO (1) wherein A is at least one element selected from the group consisting of Li, Na, K, Rb and Cs, Ln is at least one element selected from rare earth elements including Y but excluding Eu, D is at least one element selected from the group consisting of Mg, Ca, Sr and Ba, M is at least one element selected from Mo and W, x is a positive number satisfying 0