To provide a preparation for a fabric for imparting the optimum combination of water repellency, oil repellency and softness and capable of keeping this optimum combination even after high temperature washing is performed several times in the presence of a detergent.

A compound usable in the water and oil repelling treatment of a fabric is formed from an aqueous dispersion of a cationic ionomer fluorinated polyurethane based on (per) fluoropolyether having a terminal group constituted of the -NCO group reacted with a hydrogen active compound and stable against water but generating a covalent bond of non-heat resistance.