Polycarbonate resin and an optical film

(A) unit represented by the following formula (A), [Formula 1] [In the formula, R ] (B) unit represented by the following formula (B), ## STR2 ## Wherein, R ] And (C) include aliphatic diol compound and / or carbonate derived from alicyclic diol compound units (C), the following formula satisfies the (I) ~ (II), the wavelength dispersion characteristic close to the ideal wideband rice, durable stability, is excellent in flexibility, high phase difference developability, photoelastic constant is low, to provide an optical film comprising superior polycarbonate resin and from the melt processability. The molar ratio of (I) units (A) and the unit (B) (A) / (B) is 0.2 to 11.0 (II) a unit (A) + units (B) and the unit (A) + units (B) + molar ratio of the unit (C) {(A + B) / (A + B + C)} is 0.30 to 0.60