solvent alcohols having a boiling point of 110 u00b0 c or less are preferably used also the hydrophilic organic solvent is preferably those forming an azeotropic mixture with water the use of such an organic solvent improves drying of a water repellent treatment agent from this point of view it is particularly preferable to use alcohols such as ethyl alcohol or isopropyl alcohol which form an azeotropic mixture with water also the wettability variable layer forming composition of the present invention may be a wettability variable layer forming composition comprising the same components a to c as above in the same mass ratio as above and obtained by a co hydrolysis condensation polymerization reaction using these components as starting material namely the wettability variable layer forming composition of the present in invention includes a wettability variable layer forming composition in which a part of the components a and b are in a condition of being co hydrolysis condensation polymerization reacted this is because when making into a wettability variable layer forming composition there are the cases where better material qualities can be obtained if materials in condition that a co hydrolysis condensation polymerization reaction has proceeded to some extent here the condition that a part of the components a and b have already been co hydrolysis condensation polymerization reacted is preferably a condition that the amount of the substituent x in the components a and b is decreased by an amount in a range from 10 mol to 90 mol and particularly in a range from 25 mol to 75 mol compared to the input amount this is because when less than the above range there is a possibility that the material qualities of the finally obtained layer have defects whereas when exceeding.