PROBLEM TO BE SOLVED: To provide a polymer for a moisturizer having excellent moisturizing property, application feel (elasticity) and residual feel (friction, adhesiveness) when used as a moisturizer. SOLUTION: The polymer for a moisturizing agent of the present invention has a structural unit (a) derived from an unsaturated monomer (A) having a lactam structure, and an unsaturated monomer (B) represented by a specific general formula. It has a structural unit (b) of origin and has a weight average molecular weight of 80,000 or more. [Selection diagram] None【課題】保湿剤としたときの保湿性、塗布感触（弾力感）、残存感触（摩擦感、粘着感）が優れる保湿剤用ポリマーを提供する。【解決手段】本発明の保湿剤用ポリマーは、ラクタム構造を有する不飽和単量体（Ａ）由来の構造単位（ａ）と、特定の一般式で表される不飽和単量体（Ｂ）由来の構造単位（ｂ）とを有し、重量平均分子量が８００００以上である。【選択図】なし
