A resin composition includes a polymer (A) mainly containing a structural unit represented by following Formula (1): [chemical expression included] wherein m represents an integer of 2 to 10; X1 and X2 are each hydrogen atom, hydroxyl group or a functional group that can be converted into a hydroxyl group, wherein at least one of X1 and X2 is hydroxyl group or a functional group that can be converted into hydroxyl group; R1, R2 and R3 are each hydrogen atom, hydroxyl group, a functional group that can be converted into hydroxyl group, an alkyl group, an aryl group, an aralkyl group or a heteroaryl group, wherein the plural R1s may be the same as or different from each other; and a vinyl alcohol polymer (B).