To obtain a support which can prevent curling in processing or fabri cating, such as surface treatment, coating, or slitting, and has good flatness by providing a given difference in refractive index in the thicknesswise direction between the front and back surfaces of a support and winding the support with the surface having lower refractive index facing inward.

This support comprising a syndiotactic polystyrene polymer, which has been oriented and heat set in the longitudinal and transverse directions, wherein the difference in refractive index in the thicknesswise direction between the front and back surfaces of the support is not less than 4×10-3 and the support is wound so that the surface having a lower refractive index in the thicknesswise direction of the support faces inward. The difference in refractive index in the thicknesswise direction between the front and back surfaces of the support may be created by any method, for example, a method wherein, in the production of the support, a difference in temp. is forcibly created between the front and backs surfaces of the support is created in any one of longitudinal stretching, transverse stretching, and heat setting steps, or a method wherein, in the production of the support, dissimilar polymers are laminated by coextrusion.