An organosiloxane graft polyvinyl alcohol polymer contains a structural unit shown by the following general formula (1), wherein M1 and M2 represent a hydrogen atom, an acetyl group, or a siloxane group shown by the following general formula (2), provided that at least one of M1 and M2 is a siloxane group shown by the general formula (2); and A represents a single bond or a linking group, wherein R1 represents a monovalent organic group having 1 to 6 carbon atoms; R2, R3, and R4 each represent a monovalent organic group having 1 to 6 carbon atoms or a siloxy group shown by —OSiR5R6R7, where R5, R6, and R7 each represent a monovalent organic group having 1 to 6 carbon atoms; “n” represents an integer of 1 to 10; and “a” represents an integer of 0 to 2.