An Li-containing α-sialon phosphor particle by mixing a silicon nitride or nitrogen-containing silicon compound powder, an AlN-containing aluminum source, an Li source and an Eu source, firing the mixture at 1,500 to 1,800° C. in a nitrogen-containing inert gas atmosphere under atmospheric pressure to obtain a lithium-containing α-sialon powder working out to a starting material, adding and mixing an additional lithium source to the powder, and re-firing the obtained mixture at a temperature lower than the above firing temperature or at a temperature of 1,100° C. to less than 1,600° C., at 1,100° C. to less than 1,600° C., in a nitrogen-containing inert gas atmosphere under atmospheric pressure.