The present invention provides a means for improving the elastic modulus (rigidity), heat resistance, toughness, and impact resistance of a resin to provide these properties in a good balance. The present invention provides a polymer microparticle-dispersed resin composition containing 100 parts by weight of a resin and 0.1 to 150 parts by weight of polymer microparticles each containing at least two layers: a crosslinked polymer layer and a coating polymer layer, the resin composition having a particle dispersity of the polymer microparticles in the resin of not lower than 50%, the crosslinked polymer layer including 50% by weight to 99% by weight of at least one monomer having a Tg, as determined as a homopolymer, of not lower than 0° C., and 50% by weight to 1% by weight of at least one monomer having a Tg, as determined as a homopolymer, of lower than 0° C.