Abstract: The purpose of the present invention is to provide an aqueous hair cosmetic which contains a lower alcohol such as ethanol and water and is used by spraying in the form of a mist, wherein the hair cosmetic imparts a desired shape, smoothness, and water repellency to hair and has excellent retention of these effects. The present invention relates to a hair cosmetic characterized by containing: (A) a copolymer including a polysiloxane structure and a polyoxyalkylene structure in a main chain, and a side chain having a trialkoxysilane group or a silanol group; (B) a cationic surfactant; (C) a lower alcohol; and (D) water, and a hair treatment method using the same.

Abstract: The purpose of the present invention is to provide a hair treatment method that permits a suitable amount of a component having a hair treatment effect to be deposited uniformly on the hair, and that has exceptional persistence of effects in which hydrophobicity, combability, and smoothness is restored by appropriate heat treatment to hair that has been damaged and in which these effects can be maintained for an extended period of time. The present invention pertains to a hair treatment method characterized by including: (1) a step for applying, to hair, a hair treatment agent containing a copolymer that includes a polysiloxane structure and a polyoxyalkylene structure in the main chain, the copolymer having a side chain that has a trialkoxysilane group or a silanol group; (2) a step for subjecting the hair to heat treatment at 40-230° C.; and (3) a step for rinsing the hair.