PURPOSE: To protect effectively a core substance by coating the core substance with a porous bimolecular film, immersing the core substance as such in a saturated soln. or lipids when the core substance is a solid having ruggedness on the surface part and forming a bimolecular layer of the lipids.

CONSTITUTION: A core substance to be included is at least one substance selected from living cells, fresh tissue, physiological active substances, nutrients, vitamins, enzyme substrates, stabilizers, fertilizers and drugs. The core substance is coated with a porous high molecular film originated in organisms and selected from muramic acid, gelatin, carrageenan, etc. When the core substance is a solid having ruggedness on the surface part, the substance as such is immersed in a saturated soln. of lipids (e.g., phospholipids), wherein dodecane, hexane, ethyl alcohol, water, etc., are used as the medium of the saturated soln., to form a bimolecular layer on the pore part in the porous high molecular film or in the recess of the core substance. Consequently, the substance is included with damaging the shape and function of the core substance and can be stably preserved.