Provided is a thermosetting resin composition which exhibits excellent workability, and which is capable of obtaining, as a result of being cured, a highly reliable cured product (molded article) exhibiting excellent heat resistance and mechanical strength. This thermosetting resin composition includes: a polyalkenyl phenol resin (A); an aromatic polymaleimide compound (B); and a polymerization initiator (C). The polyalkenyl phenol resin (A) has, in a molecule thereof, at least one aromatic ring unit (al) which has a phenolic hydroxyl group having a 2-alkenyl group bonded thereto, and at least one aromatic ring unit (a2) having a phenolic hydroxyl group which does not have a 2-alkenyl group bonded thereto. Each of the aromatic ring units is bonded by a linking group having a main chain which is not formed by an aromatic ring. When m represents the number of the aromatic ring units (a1), and n represents the number of the aromatic ring units (a2), the ratio of m to (m+n) is 40-90%. The polyalkenyl phenol resin (A) is included in an amount at which the amount of 2-alkenyl groups becomes 0.4-1.5 mol per mol of maleimide groups in the aromatic polymaleimide compound (B).