To provide a one-bath, scouring/bleaching method for a blanket material to be raised of cotton or mixed cotton, having a natural feeling of softness characteristic of cotton.

This method uses enzyme protopectinase and hydrogen peroxide, as the softening agents for a blanket material raising process, simultaneously in the same bath, to decompose and remove pectin, impurities and coloring materials present in the cotton fibers for the blanket material, by one-bath treatment at low temperature for a short time, while leaving natural wax component (which is traditionally considered to be an impurity) not molten nor decomposed/removed.