A method for producing a liposome comprising a lipid bimolecular membrane composed of: an inner membrane constituted with a lipid which contains one or more functional lipids selected from the group consisting of a charged lipid, a polarized lipid, a lipo-soluble lipid and a water-soluble lipid; and an outer membrane constituted with a lipid which contains or does not contain one or more functional lipids selected from the group consisting of a charged lipid, a polarized lipid, a lipo-soluble lipid and a water-soluble lipid, wherein an amount of one of the functional lipids contained in the inner membrane is larger than an amount of the one of the functional lipids contained in the outer membrane, the method comprising the steps of -: a first emulsion preparation step comprising mixing: supercritical or semi-supercritical carbon dioxide or an organic solvent; a water-soluble solvent (W 1); and a mixed lipid component (F 1) which forms an inner membrane of the liposome so as to prepare a W 1 /CO 2 emulsion or a W 1 /O emulsion; a second emulsion preparation step comprising adding the W 1 /CO 2 emulsion or the W 1 /O emulsion prepared in the step to a mixture of a water-soluble solvent (W 2) and a mixed lipid component (F 2) which forms an outer membrane of the liposome with stirring so as to prepare a W 1 /CO 2 /W 2 emulsion or a W 1 /O/W 2 emulsion; eliminating the solvents contained in the W 1 /CO 2 /W 2 emulsion or the W 1 /O/W 2 emulsion prepared in the step so as to prepare a suspension of the liposome comprising the inner membrane composed of F 1 and the outer membrane composed of F 2, wherein an amount of one of the functional lipids contained in F 1 of the step is larger than an amount of the one of the functional lipids contained in F 2 in the step. an inner membrane constituted with a lipid which contains one or more functional lipids selected from the group consisting of a charged lipid, a polarized lipid, a lipo-soluble lipid and a water-soluble lipid; and an outer membrane constituted with a lipid which contains or does not contain one or more functional lipids selected from the group consisting of a charged lipid, a polarized lipid, a lipo-soluble lipid and a water-soluble lipid, wherein an amount of one of the functional lipids contained in the inner membrane is larger than an amount of the one of the functional lipids contained in the outer membrane, the method comprising the steps of -: a first emulsion preparation step comprising mixing: supercritical or semi-supercritical carbon dioxide or an organic solvent; a water-soluble solvent (W 1); and a mixed lipid component (F 1) which forms an inner membrane of the liposome so as to prepare a W 1 /CO 2 emulsion or a W 1 /O emulsion; a second emulsion preparation step comprising adding the W 1 /CO 2 emulsion or the W 1 /O emulsion prepared in the step to a mixture of a water-soluble solvent (W 2) and a mixed lipid component (F 2) which forms an outer membrane of the liposome with stirring so as to prepare a W 1 /CO 2 /W 2 emulsion or a W 1 /O/W 2 emulsion; eliminating the solvents contained in the W 1 /CO 2 /W 2 emulsion or the W 1 /O/W 2 emulsion prepared in the step so as to prepare a suspension of the liposome comprising the inner membrane composed of F 1 and the outer membrane composed of F 2, a first emulsion preparation step comprising mixing: supercritical or semi-supercritical carbon dioxide or an organic solvent; a water-soluble solvent (W 1); and a mixed lipid component (F 1) which forms an inner membrane of the liposome so as to prepare a W 1 /CO 2 emulsion or a W 1 /O emulsion; supercritical or semi-supercritical carbon dioxide or an organic solvent; a water-soluble solvent (W 1); and a mixed lipid component (F 1) which forms an inner membrane of the liposome so as to prepare a W 1 /CO 2 emulsion or a W 1 /O emulsion; a second emulsion preparation step comprising adding the W 1 /CO 2 emulsion or the W 1 /O emulsion prepared in the step to a mixture of a water-soluble solvent (W 2) and a mixed lipid component (F 2) which forms an outer membrane of the liposome with stirring so as to prepare a W 1 /CO 2 /W 2 emulsion or a W 1 /O/W 2 emulsion; eliminating the solvents contained in the W 1 /CO 2 /W 2 emulsion or the W 1 /O/W 2 emulsion prepared in the step so as to prepare a suspension of the liposome comprising the inner membrane composed of F 1 and the outer membrane composed of F 2,