PROBLEM TO BE SOLVED: To provide the second agent composition for dyeing hair or bleaching hair, which controls an unpleasant odor on treatment and exhibits sufficient bleaching power.SOLUTION: Provided is the second agent composition for dyeing the hair or bleaching the hair, which is to be mixed with the first agent composition containing an alkali agent, comprises the following components (A) to (D), and has pH of 1 to 6 at 25°C. (A) An organic amine having at least one hydrophobic chain or its salt, (B) an oily component liquid at 25°C under the ordinary pressure, (C) an anti-oxidizing agent, and (D) water.COPYRIGHT: (C)2009,JPO&INPIT