Electrostatically bonded vesicles containing metal fine particles

The following combinations of the first polymer of (a) or (b), the following (c) and or the second polymer and film formed by the (d) (provided that (b) and (d) a excluding), formed by a membrane which is partially crosslinked cationic segment and an anionic segment in the polymer, vesicles containing metal fine particles. First polymer: (A) Block copolymer I having an uncharged hydrophilic segment and a cationic segment, (B) an amino acid polymer having a cationic segment I The second of the polymer: (C) block copolymer II having a non-charged hydrophilic segment and an anionic segment, (D) an amino acid polymer II having an anionic segment.