PURPOSE: To provide the process for producing the liposome which can concentrate the physiologically active material in the drugs to be included in the liposome up to a high concn. and high density without denaturing this material, thereby yielding the liposome of high capsulation efficiency and capsulation yield.

CONSTITUTION: This process has a 1st stage of rotating a rotor 3 having a heat transfer surface 3a disposed in a vacuum chamber 2, supplying the liquid chemical contg. the physiologically active material into this vacuum chamber 2 and instantaneously heating the thin film of the liquid chemical to evaporate its moisture while forming this film on the heat transfer surface 3a by the rotating force of the rotor 3, thereby concentrating the liquid chemical to the high concn. and the high viscosity and a 2nd stage of adding and mixing a liposome forming lipid mixture with the concd. liquid chemical and subjecting the resulted mixture to a suspension treatment, thereby forming the liposome.