PURPOSE: To suppress reduction in cell density by intake of emulsion by adding a specific substance such as polyvinyl-based compound to a culture system consisting of a culture solution and a solvent not miscible with the culture solution.

CONSTITUTION: Animal cells, etc., are cultured in a culture system consisting of a serum-free aqueous culture solution containing inorganic salt, vitamin, glucose, etc., and a nonhydrophilic solvent such as fluorocarbon which is not substantially miscible with the culture solution and not inhibiting formation of cells in the presence of at least one compound selected from polyvinyl-based compound such as polyvinyl pyrrolidone, polyglycol based compound such as polyethylene glycol and cellulose derivative in a suspended state by perfusion method. Consequently, sucking of cells in emulsion of water and solvent is limited to the minimum and cells can be maintained in high density and multiplied.