PURPOSE: To obtain a polymer molding having a surface excellent in water repellency, oil repellency and ice contact resistance, by subjecting the surface of a polymer molding to a fluorination treatment and subjecting the surface again to a postfluorination treatment thereby to fluorinate the chemically active groups produced subsidiarily with fluorine gas.

CONSTITUTION: The surface of a polymer molding is subjected to a prefluorination treatment. The chemically active groups (e.g., oxygen-containing functional groups) produced subsidiarily on the superficial layer are subjected to either (1) a postfluorination treatment with fluorine gas at a temperature of about 90W 200°C which is higher than the temperature of the prefluorination treatment, or (2) after hydrolysis, a postfluorination treatment with fluorine gas at a temperature of about 50W200°C which is higher than the prefluorination temperature. With respect to the purity of the fluorine gas, an oxygen content of below 1% is sufficient and, accordingly, commercially available fluorine gas can be used. The thickness of the fluorinated layer (protective layer) formed by the prefluorination treatment can be controlled by suitably selecting the reaction condition for the fluorine gas used.