The invention is directed to a two-part hair cosmetic for hair dyeing or bleaching which includes a first agent containing an alkaline agent and a second agent containing hydrogen peroxide and a squeeze container for discharging a mixed solution of the first agent and the second agent. The first agent or second agent contains a foaming agent. The mixed solution thereof has a viscosity (25° C.) of from 1 mPa·s to 100 mPa·s. The ratio between the total volume of the first and second agents and the inner volume of the container body is in the range of from 0.30 to 0.60.