PURPOSE: To increase water resistance of the support, by bringing a mixture of cell bodies of a microorganism and aqueous polyvinyl alcohol of a specific concentration into contact with an aqueous sulfate of a specific concentration and an aqueous borate of a specific concentration.

CONSTITUTION: Cell bodies of a microorganism is mixed with 1W30% polyvinyl alcohol (PVA) aqueous solution, and the mixture is treated with an aqueous sulfate over 15% concentration and an aqueous borate over 5% concentration to immobilize the cell bodies on the support. In an embodiment, the cell bodies are mixed with the aqueous PVA, the mixture is extruded out through nozzles into an aqueous solution containing a sulfate and a borate to effect solidification. Then, the particles are collected. According to the method, PVA can be solidified in a short time, and tough and water-resistant support including immobilized cell bodies of a microorganism can be massively produced.