The present invention provides an optical film exhibiting wavelength dispersion such that a retardation value is smaller on the shorter wavelength side, and capable of being also formed comparatively thinly.The optical film of the present invention is an optical film including a polyimide-based polymer represented by the following general formula (I).In the formula (I), m is 40% by mol or more and 100% by mol or less. R1 and R2 each independently denote a substituent having a carbon-carbon double bond or a triple bond. A, A′, B, B′, E, G, and H each denote a substituent, and small letters corresponding to these alphabets denote substitution number thereof. X and Y each independently denote bond part such as a covalent bond. The substituents having a carbon-carbon double bond or a triple bond represented by R1 and R2 are a substituted or unsubstituted aryl group, a substituted or unsubstituted vinyl group, and a substituted or unsubstituted ethynyl group.