PROBLEM TO BE SOLVED: To provide a gene inducing agent composition remarkably excellent in gene inducing activity wherein demerits of non-viral vector and viral vector are solved, and merits of both are possessed.SOLUTION: There is disclosed a gene inducing agent composition including at least one part of cationic polymers, nucleic acids, and adenoviruses. It is preferred that the cationic polymer is a cationic star polymer having 4 or more cationic polymer chains. Especially it is preferred that the cationic star polymer has a benzene ring as a nucleus and cationic polymer chains are bound to the nucleus as a branched chain.
