To provide a new phosphor of which fluorescence contains much red light component and has a large full width at half maximum, the crystal phase represented by the formula [I] is included in the phosphor.
R3−x−y−z+w2MzA1.5x+y−w2Si6−w1−w2AlW1+w2Oy+w1N11−y−w1 [I]
(R represents La, Gd, Lu, Y and/or Sc, M represents Ce, Eu, Mn, Yb, Pr and/or Tb, A represents Ba, Sr, Ca, Mg and/or Zn, and x, y, z, w1 and w2 are the numeric values in the following ranges:
( 1/7)≦(3−x−y−z+w2)/6<(½),
0<(1.5x+y−w2)/6<(9/2),
0<x<3,
0≦y<2,
0<z<1,
0≦w1≦5,
0≦w2≦5, and
0≦w1+w2≦5.)