Provided are an optical film which has high heat resistance, high transparency, and high mechanical strength, and has a sufficient retardation compensation function with a reverse wavelength dispersion characteristics, and a polarizing plate having such an optical film and a polarizer. Further, an image display apparatus of high quality using such a polarizing plate is provided. The optical film of the present invention includes a (meth)acrylic resin having a lactone ring as a main component, in which an in-plane retardation Re(450) at a wavelength of 450 nm/an in-plane retardation Re(600) at a wavelength of 600 nm is less than 1.0.