Provided is a polymer having a repeating unit represented by the following formula (1). In the formula, Ar1, Ar2, and Ar3 each independently represent an aromatic hydrocarbon group or aromatic heterocyclic group, which may optionally have a substituent group, and n represents an integer equal to 4 or greater. Multiple aromatic hydrocarbon groups and aromatic heterocyclic groups may be linked directly, or through linking groups.