A heat-resistant cured product is efficiently produced by obtaining a semi-cured product where a curable resin composition containing a (meth)acrylate monomer, a non-conjugated vinylidene group-containing compound and a thermal radical-polymerization initiator is processed by at least one of photoirradiation and heating to give a semi-cured product having a complex viscosity of from 105 to 108 mPa·s at 25° C. and at a frequency of 10 Hz; and putting the semi-cured product in a forming die for pressure formation therein, and heating it therein for thermal polymerization to give a cured product.