A process of readily producing a patterned birefringent product excellent in resolution and heat-resistance is provided. Said process comprises at least the following steps [1] to [3] in order: [1] preparing a birefringence pattern builder which comprises an optically anisotropic layer comprising a polymer, and said optically anisotropic layer has a retardation disappearance temperature in the range higher than 20° C., at said retardation disappearance temperature in-plane retardation becomes 30% or lower of the retardation at 20° C. of the same optically anisotropic layer, and said retardation disappearance temperature rises by light exposure; [2] subjecting the birefringence pattern builder to patterned light exposure; [3] heating the laminated structure obtained after the step [2] at 50° C. or higher and 400° C. or lower.