A novolak resin including a partial structure represented by -C(CF 3 )H-. In addition, there are provided a photosensitive resin composition containing the above-described novolak resin and a photosensitizing agent. In addition, there is provided an epoxy resin having a partial structure represented by -C(CF 3 )H-. In addition, there is provided a curable resin composition containing the novolak resin or the epoxy resin. In addition, there is provided a cured substance obtained by curing the composition. In addition, there is provided a production method for a novolak resin, including reacting an aromatic compound with fluoral in a presence of an acid catalyst to produce a novolak resin having a partial structure represented by -C(CF 3 )H-. Further, there is provided a production method for an epoxy resin, including an epoxidation step of reacting a novolak resin having a partial structure represented by -C(CF 3 )H-with epihalohydrin in a presence of a base.