High reliability because of that the wavelength dispersion changes little less display unevenness due to the position dependency of the phase difference change, and provides a production method of a retardation film having reverse wavelength dispersion property. The following formula (1) and _{(2): 0.70 <Re 1} [450] / Re 1 [550] <0.97 ··· (1). ^{1.5 × 10 -3 <Δn <6.0} × 10 -3 ··· (2) ( wherein, Re ₁ [450] and Re ₁ [550], respectively, measured with light having a wavelength of 450nm and 550nm of the 23 ℃ the in-plane retardation value of a retardation film, Δn is a method of manufacturing a retardation film satisfying a birefringence in the plane of the retardation film measured with light having a wavelength of 550nm). The method subsequently after the stretching process, the stretching step of for a process, the polymer film for supplying the transport of a long polymer film in the feeding direction extends in the transverse direction, a first contraction step of shrinking the polymer film in the transverse direction , and, after the first contraction process, a shrinkage temperature in a polymer film to shrink temperature T ₁ (℃) and the second contraction step in the and a second contraction process for shrinkage in the transverse direction, a first contraction step T ₂ (℃) is the following formula (3) satisfies _{1 <(T 1 -T 2)} ≤10 ··· (3).