Disclosed is a method for hair shaping treatment that is straightening treatment or permanent waving treatment, including at least the steps of: applying a first agent containing a reducing agent to hair, and leaving the hair for a predetermined period of time； washing off the first agent applied to the hair； applying a second agent containing an oxidizing agent to the hair, and leaving the hair for a predetermined period of time； and washing off the second agent, wherein the method for hair shaping treatment further includes the step of: applying a hair treating liquid containing gold nanoparticles to the hair. Also disclosed is a hair treating liquid for hair shaping treatment that is applied to hair in hair shaping treatment, the hair treating liquid including gold nanoparticles.
