The purpose of the invention is to both improve the luminance of a SCASN-based phosphor and achieve deep-color rendering properties. Provided is a red phosphor having a main crystal phase having the same crystal structure as a crystal structure of CaAlSiN3, the main crystal phase represented by the general formula MAlSiN3, wherein an internal quantum efficiency, as measured when the red phosphor is excited by light having a wavelength of 455 nm, is 71% or more, and M in the general formula represents an element group containing at least three elements selected from Eu, Sr, Mg, Ca, and Ba, the element group containing Eu, Sr, and Ca as essentials, and a Eu content is 4.5 mass % or more and 7.0 mass % or less, a Sr content is 34.0 mass % or more and 42.0 mass % or less, and a Ca content is 0.8 mass % or more and 3.0 mass % or less.