The present invention relates to a hair treatment agent enabling hair to be permed or dyed, and a method for perming the hair using the hair treatment agent, a method for dyeing the hair using the hair treatment agent, or a method for simultaneously perming and dyeing the hair using the hair treatment agent. The hair treatment agent according to the present comprises: 20 to 25 wt% of 2-mercapto-4-butyrolactone； more than 0 to 0.1 wt% or less of disodium EDTA； more than 0 to 0.1 wt% or less of panthenol； more than 0 to 0.1 wt% or less of tocopheryl acetate； 1.0 to 3.0 wt% of PEG-7-glyceryl cocoate； 1.0 to 4.0 wt% of PPG/PEG-17/6 copolymer； 0.1 to 0.5 wt% of sodium citrate； more than 0 to 0.1 wt% or less of hydrolyzed collagen； more than 0 to 0.1 wt% or less of hydrolyzed keratin； more than 0 to 0.1 wt% or less of citric acid； and a remainder consisting of purified water. The hair treatment agent according to the present invention does not give damage to hair, forms the hair in various forms, enables the hair to be dyed in various colors, and enables a user to simultaneously have procedures of a perm and dyeing the hair. Further, the hair treatment agent according to the present invention is capable of remarkably reducing procedure time, and is capable of obtaining an economic effect due to the cost reduction by removing the necessity of using a second preparation when undergoing the procedure of a perm. Further, the hair treatment agent according to the present invention is capable of improving satisfaction of an operator by preventing an unpleasant smell from being generated during the procedures of a perm or dyeing the hair.본 발명은 모발에 퍼머 또는 염색을 가능케 하는 모발처리제와, 이를 이용한 모발의 퍼머 방법, 염색 방법 또는 모발의 퍼머 및 염색을 동시에 수행하는 방법에 관한 것이다.본 발명에 의하면, 모발에 손상을 가하지 않으면서 모발의 모양을 다양한 형태로 성형시키거나, 다양한 색깔로 염색할 수 있도록 하며, 퍼머와 염색의 동시 시술이 가능하도록 한다. 또한, 본 발명에 의하면, 퍼머 시술 시 제2제재를 사용하지 않아도 되어, 시술 시간을 현저히 단축시킬 수 있고, 원가 절감에 따른 경제적 효과도 거둘 수 있다. 또한, 본 발명에 의하면, 퍼머나 염색 시술 중에 불쾌한 냄새가 발생되지 않아 시술자의 만족도를 향상시킬
