PURPOSE: To provide an extremely easily manufacturing method capable of easily manufacturing open-cell cell structures with high foaming magnification extending from thin film form to thick modified form, and particularly suitable for the manufacture of an in vivo decomposable absorptive cell structure expected to be used particularly as living body material.

CONSTITUTION: An organic synthetic polymer is dissolved in a mixed solvent consisting of a solvent capable of dissolving this polymer and a nonsolvent having a boiling point higher than this solvent and incapable of dissolving the polymer to prepare a polymer solution, this polymer solution is filled in a die, and the mixed solvent is evaporated at a temperature lower than the boiling point of the solvent, whereby the polymer is precipitated to manufacture a cell structure.