A thermosetting resin composition comprises a component (A) that is a compound having an imide group and a carboxy group in one molecule, and a component (B) that is a polymer having a repeating unit represented by the following general formula (1). R.sup.1 and R.sup.2 in formula (1) are each independently a hydrogen atom or a methyl group. R.sup.3 in formula (1) is a hydrogen atom or any substituent, and a plurality of R.sup.3s may be bonded to form a ring structure. R.sup.4 in formula (1) is a hydrogen atom or an alkyl group. m and n in formula (1) are each independently an integer of 1 or more, and m/n may be 1 to 50. ##STR00001##