Washing/drying method with an aqueous solution containing surfactant

A washing/drying method comprising:

• dipping a material to be washed into an aqueous solution containing a surfactant having a water repellency selected from the group consisting of hydrocarbon surfactants having a C.sub.12 -C.sub.18 hydrophobic alkyl group, fluorine surfactants having a C.sub.6 -C.sub.12 fluorinated alkyl group, and hydrophobic silicon surfactants so that at least one molecular layer of the water repellent surfactant is attached to the surface of the material to be washed,
• heating the material to be washed with steam at a temperature of less than 100.degree. C. in an atmosphere having a reduced pressure such that, in the reduced pressure atmosphere, the boiling point of water becomes less than 100.degree. C., and
• drying the material by at least one of vacuum drying, shaking off, blowing gas thereon, and heating.