The present invention provides a polymer film for suppressing roll deviation and bulky volume of a film roll. A long film (10) is provided with knurling (11) on each side. The knurling (11) is formed in a wavy cross-sectional shape in which convex portions (15) and concave portions (16) are alternately continuous in the width direction (Z2). The convex portions (15) and the concave portions (16) extend in the longitudinal direction of the film (10), respectively. When the width of the convex portions (15) is 100, the width of the concave portions is in the range of 80 or more and 120 or less. The radius of curvature R2 at the vertex (15a) of the convex portion (15), the radius of curvature R2 at the bottom point (16a) of the concave portion (16), and the thickness T of the film (10) in the cross section in the width direction (Z2) meets R1 > R2 + T.