To provide a new fluorescent substance having a wide half value width, and to provide a method for producing the fluorescent substance.

The fluorescent substance containing a crystal phase represented by formula [A]: R3-x-y-z+w2MzA1.5x+y-w2Si6-w1-w2Alw1+w2Oy+w1N11-y-w1 [A] [wherein, R is La, Gd, Lu, Y or Sc; M is Ce, Eu, Mn, Yb, Pr or Tb; A is Ba, Sr, Ca, Mg or Zn; x, y, z, w1 and w2 are each a number satisfying the expressions of (1/7)(3-x-y-z+w2)/6(1/2); 0(1.5x+y-w2)/6(9/2); 0x3; 0y2; 0z1; 0w15; 0w25 and 0w1+w25] is produced by using an alloy containing two or more metal elements contained in the crystal phase as at least a part of a raw material.