PURPOSE: To shorten the time required for perming and hair dyeing treatments by using a hairdressing liquid prepd. by mixing an acidic hair dyeing liquid essentially consisting of benzyl alcohol and parabene, a perming liquid and a moisture retaining liquid for hair essentially consisting of propylene glycol.

CONSTITUTION: The hairdressing liquid prepd. by mixing the acidic hair dyeing liquid essentially consisting of the benzyl alcohol and parabene, the perming liquid essentially consisting of ammonium thioglycolate and the moisture retaining liquid for hair essentially consisting of the propylene glycol is applied on the entire region of additional spreading and thereafter, a cap is put on and the head is heated by an accelerator. After the cap is removed, the moisture retaining liquid for hair essentially consisting of the propylene glycol is applied over the entire part of the hair to be treated. The acidic hair dyeing liquid essentially consisting of the benzyl alcohol and parabene which are manicure agents for hair is thereby decomposed and the regular dyeing of the hair is attained. The perming II agent essentially consisting of promic acid is further applied by a foaming device on the hair to treat the hair, by which the perming and hair dyeing are simultaneously attained.