PURPOSE: To enable freezing and cryopreservation of various cells and tissues without damaging them, by diffusing a fixed amount of a specific cryoprotectant to a biological cellular material and lowering the temperature of the biological cellular material to a preservation temperature.

CONSTITUTION: A cryoprotectant containing a chemical composition of a phosphomonoester or phosphodiester catabolite of a phosphoglyceride free of fatty acid residues is dispersed in a concentration of twice as much as a catabolite generally existing in a biological cellular material, which is preferably a plant. Further the cellular material is introduced into a cooling chamber and the preservation temperature is lowered to prevent damage in freezing and/or freezing and thawing of tissue.