The object of the present invention is to provide a thermosetting resin composition which can provide a cured material which is excellent in heat resistance, electrical properties, and flexibility, and has storage stability before curing, and in order to achieve the object, the present invention provide a thermosetting resin composition containing a polyurethane resin (A) which has the structure represented by the following general formula (1) and/or the general formula (2), and an epoxy resin (B). (In the chemical formulae, X represents a residue in which two phenolic hydroxyl groups are excluded from a phenol compound having two or more phenolic hydroxyl groups in the molecule.)