The present invention is a fluorescent material characterized by being represented by a composition of the following formula (1) and having a crystal lattice distortion obtained from a Williamson-Hall plot by X-ray diffraction within the range of 0.0005 to 0.0020. (Sr,Ca,M)3-xMgSi2O8:Eux  formula (1) wherein M is at least one rare earth metal elements selected from the group consisting of Sc, Y, Gd, Tb and La, and 0.01≤x≤0.10. Also, the present invention is a light-emitting device including the fluorescent material, and a light source that emits light by irradiating the fluorescent material with excitation light. Furthermore, the present invention is a method for producing the fluorescent material, including the steps of: obtaining an aqueous slurry of a raw material; and spray-drying the aqueous slurry with hot air at 80 to 300° C.