To provide heat expansible microcapsules and hollow resin particles with sharp particle size distribution, hollow resin particles with excellent heat resistance, and to provide methods for producing the same.

The invention relates to the heat expansible microcapsules and hollow resin particles comprising at least one resin selected from a group comprising polyurethane resins, epoxy resins and polyamide resins, and has 1-20% of particle diameter coefficient of variation. The heat expansible microcapsules are obtained by the following method. The method for producing expansible microcapsules comprising polymer (X) comprises a step preparing an O/W type emulsion (E) by dispersing a mixture (D) comprising a polymer precursor (a) and a solvent (C), in water, a step mixing the emulsion (E) with a polymer precursor (b) or a solution (F) of (b) and then carrying out an interfacial polymerization. The hollow resin particles are obtained by heating the heat expansible microcapsules.