Provided are a resin composition for general-purpose LED reflectors, which discolors little through thermal deterioration and is excellent in heat discoloration resistance, which can provide an LED lamp using it and having a long life, which is relatively inexpensive and has good storage stability, and which is excellent in handleability and workability, and an LED reflector and an LED luminaire using the resin composition.The resin composition is a dry-type unsaturated polyester resin composition containing at least an unsaturated polyester resin, a polymerization initiator, an inorganic filler, a white pigment, a release agent and a reinforcing material, wherein the unsaturated polyester resin is within a range of from 14 to 40% by mass relative to the entire amount of the composition, the total amount of the inorganic filler and the white pigment is within a range of from 44 to 74% by mass relative to the entire amount of the composition, and the proportion of the white pigment to the total amount of inorganic filler and the white pigment is at least 30% by mass.