To provide a cosmetic base having high compatibility with LPG as well as high moisture resistance and good hair rinsing ability, and to provide a cosmetic compounded with the base.

This cosmetic base comprises a polymer which is obtained by polymerization of a monomer component comprising (A) 25-70 wt.% of a monomer of formula (I) (R1 is H or CH3; R2 is H, a 1-12C alkyl or C(CH3)2 CH2COCH3; and R3 is H or a 1-12C alkyl), (B) 5-60 wt.% of a monomer of formula (II) (R4 is a 3C or 5C alkylene), (C) 2-20 wt.% of a monomer of formula (III) (R5 is H or CH3; R6 is H or COOH; and R7 is H, CH3 or CH2COOH), (D) 3-40 wt.% of a monomer of formula (IV) (R8 is H or CH3, R9 is a 1-4C alkylene; R10 and R11 are each H or a 1-8C alkyl; and A is O or NH) and (E) 2-30 wt.% of a monomer of formula (V) (R12 and R15 are each H or CH3; R13 and R14 are each a 2-4C alkylene; and m and n are each 0-50, except that m and n are both 0). The other objective cosmetic compounded with the above base is provided.