After collecting the hair of a woman at her age of 32 which had not been chemically treated, bundles of hair was produced by weighing 1.2 g each for an experiment. To group them into healthy hair and damaged hair, the hair permed on the healthy hair was called perm hair and that permed on the damaged one decolored up to level 8, called dyed hair. The same perm solution 1 was applied and wound,and they were treated by middle rinsing differently before neutralization, and divided into control group and experiment group. In conclusion, as a result of experiments differentiating various conditions in the stage of middle rinsing which goes through the most radical change in a perm treatment, if importance is attached to curl formative power of hair only, a satisfactory result would be obtained by penetrating treatment such as keratin and ceramide sufficiently after the middle rinsing and neutralizing it. Considering the health of hair, rather not doing middle rinsing or having a time of removing moisture and leaving the hair so that it can make a stable combination in case of rinsing for curl formative power is a method by which the customer and practitioner can get a satisfactory result.