PURPOSE: To enable supply of an adequate amount of a culture medium according to cultivation conditions of cells, etc., in a cultivation vessel, by regulating liquid flow rate of a liquid feeding means for a permeated liquid recovery pipe based on measured values of a concentration sensor capable of sensing concentration of a prescribed component in the permeated liquid.

CONSTITUTION: In a culture solution circuit 33, a culture solution containing cells, etc., in a cultivation vessel 2 is circulated through a separating means 32 capable of permeating a liquid component in the culture solution at a constant speed. A permeated liquid recovery pipe 4 is connected from the separating means 32 through a liquid feeding means 41 to a drain 43. Furthermore, a liquid fresh culture medium is fed into the vessel 2 based on the liquid surface level in the cultivation vessel 2 by a culture medium feeding means 5. A sampling pipe (d) is provided with a concentration sensor 62 capable of sensing concentration of a prescribed component in the permeated liquid to branch and connect between the liquid feeding means 41 and the drain 43 so as to enable changeover. In a controlling part 6 for permeated liquid recovery rate, liquid flow rate of the liquid feeding means 41 in the pipe 4 is regulated based on measured values of the concentration sensor 62.