To obtain a liq. cationic paste compsn. which is excellent in usability by adding a specific compd. to a copolymer formed from a lower fatty acid vinyl ester and a cationic unsatd. monomer.

This compsn. contains a base paste material obtd. by copolymerizing a lower fatty acid vinyl ester (A) and a cationic unsatd. monomer (B) and a compd. (C) of formula I (wherein R1 to R6 are each independently 1-6C alkyl; and X- is a halogen ion, etc.). Vinyl acetate and vinyl butyrate are used as monomer A. An esp. pref. example of monomer B is a compd. of formula II (wherein X- is an anion) (e. g. 2-hydroxy-3- methacryloxypropyltrimethylammonium salt). The wt. ratio of monomer A to monomer B in the copolymn. is pref. (100:1)-(100:20). The compsn. pref. contains 20-60% base paste material and 0.00005-0.5% compd. C.