A polyvinyl alcohol-based resin composition including a modified vinyl alcohol-based polymer (A) in which a polyoxyalkylene unit represented by a general formula (I) is bonded to a polyvinyl alcohol chain and a modified vinyl alcohol-based polymer (B) having a double bond in a polyvinyl alcohol chain. (In which: R1 and R2 are independently, a methyl group, an ethyl group or a hydrogen atom, and R3 is an alkyl group or a hydrogen atom. N represents a number of repeating units and is an integer of 5≤n≤70.)