A method of manufacturing a wavelength conversion member including a polycrystalline ceramics includes mixing a substance serving as a silicon source, a substance serving as an aluminum source, a substance serving as a calcium source, and a substance serving as a europium source; firing the obtained mixture to obtain an oxynitride phosphor powder; then sintering the oxynitride phosphor powder in an inert atmosphere to obtain the polycrystalline ceramics, characterized in that the sintered oxynitride phosphor powder has a composition (excluding oxygen) represented by the Formula: Cax1Eux2Si12-(y+z)Al(y+z)OzN16-z (in the Formula, x1, x2, y, and z are values such that 0