A red phosphor where the crystal phase constituting the phosphor is monoclinic Eu-activated CaAlSiN3. A red phosphor which is Eu-activated CaAlSiN3 powder having an average particle diameter of 10 μm or less as measured in the non-pulverized state by the laser scattering particle size distribution analysis. A light-emitting device comprising a blue light-emitting element, a yellow phosphor capable of converting the blue light emitted from the blue light-emitting element into yellow light, and the above-described red phosphor capable of converting the blue light emitted from the blue light-emitting element into red light. A method for producing Eu-activated CaAlSiN3, comprising firing a raw material powder comprising Ca3N2, AlN, Si3N4 and EuN at 1,400 to 2,000° C. in a nitrogen-containing atmosphere, the Ca3N2, AlN and Si3N4 giving a composition falling in the region surrounded by a straight line connecting the following four points A to D in the composition diagram of FIG. 1, and EuN being contained in an amount of 0.01 to 10 parts by weight as Eu per 100 parts by weight in total of Ca3N2, AlN and Si3N4.