The present invention provides: a phosphor which can be combined with a blue LED to emit white light having a low color temperature as in the case where the phosphor is used singly, has a broad fluorescence spectrum, high light emission efficiency, and thermal/chemical stability, and rarely undergoes the deterioration in brightness at higher temperatures. This phosphor is represented by the general formula: Mx(Si,Al)2(N,O)3±y (wherein M independently represent Li or at least one alkali earth metal element; and x and y fulfill the requirement represented by the formulae: 0.52≦x≦0.9 and 0≦y≦0.3) wherein some of M are substituted by element Ce, and wherein the Si/Al atomic ratio is 1.5 to 6 inclusive, the O/N atomic ratio is 0 to 0.1 inclusive, 5-50 mol % of M's is Li, and 0.5-10 mol % of M is Ce.