This hair shaping agent contains (A) a compound represented by formula (1), and (B) water. (In formula (1), R1, R2, and R3 represent H or a group represented by formula (2) thereamong, 0 to 2 are H. In formula (2), R represents H or a carboxy group, and A1 and A2 represent H, OH, or a group represented by formula (3). In formula (3), one of X, Y, and X represents the bonding site of the C in formula (2), and the remainders represent H or -CH(OH)COOH.).本發明之毛髮變形處理劑含有以下之成分(A)及(B)。(A)式(1)所表示之化合物[式(1)中,R1、R2及R3表示H或式(2)所表示之基,其中0~2個為H。式(2)中,R表示H或羧基,A1及A2表示H、OH或式(3)所表示之基。式(3)中,X、Y及Z中之任一者表示與式(2)中之C鍵結之位置,剩餘者表示H或-CH(OH)COOH](B)水