The present invention is a method for hair dyeing or bleaching by discharging in a foam from a squeeze container 6 a mixed solution of a first agent A1 and a second agent A2 of a two-part hair dye or bleach composition to apply on the hair. In the present invention, the squeeze container which includes a container body 4 and a squeeze foamer 5 is used as the squeeze container 6. At least one of the first agent A1 or the second agent A2 contains a foaming agent. The mixed solution of the first and second agents has a viscosity (25°C) of from 1 mPa·s to 100 mPa·s. The first agent A1 and the second agent A2 are mixed in the container body 4 so as not to produce a foam. Squeezing is carried out with the squeeze container 6 stood upright so that the mixed solution A3 does not reach an air induct path 12 of the squeeze foamer 5. As a result, the mixed solution of the first and second agents of the two-part hair dye or bleach composition can be stably discharged in a fine foam using a squeeze container.
