Provided are an organic semiconductor element including an organic semiconductor film that includes a polymer having a repeating unit represented by the following Formula (1), the polymer, and an organic semiconductor composition and an organic semiconductor film including the polymer. In the formula, Z represent a 5-membered aromatic heterocycle. RC1 and RC2 each independently represent a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. n1 and n2 each independently represent 0 or 1. RC3 to RC10 each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group.