A method for treating hair, in which using as a boundary a depth X% in a range of 5% to 80% from the surface of hair toward the center along the long diameter axis extending through the center of the cross-section of hair, hair is divided into an A layer (a portion of a continuous color from the surface of hair to the depth X%) and a B layer (a portion including the center and having a continuous color different from the A layer, in which the depth from the surface of hair exceeds X%) and at least one value of ΔE*, Δh and ΔC* between the color of the A layer and the color of the B layer is adjusted to 3 or more to change the hue and the color tone of hair appearance depending on viewing angle of the hair. A method for dyeing hair, having Step (I) of dyeing hair with a two-part permanent hair dye agent, and Step (II) of dyeing hair with a hair dye agent comprising a dye selected from (A-l) to (A-8) .本發明係一種毛髮處理方法，其係將沿著通過毛髮剖面中心之長徑之軸自毛髮之表面朝向中心5～80%之範圍之深度X%設為邊界，將毛髮分為A層(自毛髮之表面至深度X%為止之顏色連續之部分)與B層(距毛髮之表面之深度超過X%且包含中心的與A層不同之顏色連續之部分)，使A層之顏色與B層之顏色之ΔE﹡、Δh、ΔC﹡中之一個以上之值為3以上，且使毛髮外觀之色相或色調根據觀察角度之不同變化。 本發明係一種染毛方法，其含有：步驟(I)，其係藉由二劑式永久染毛劑進行染毛；及步驟(II)，其係藉由含有選自(Α-1)～(Α-8)之染料之染毛劑進行染毛。
