To obtain the subject carrier composed of a polyurethane gel, swelling with water, having communicating pores and high strength, resistant to microbial attach and capable of immobilizing cells and microorganisms by reacting a polyol compound with an isocyanate compound and water.

The objective porous carrier for bioreactor is swellable with water, contains communicating pores, has a volume swelling ratio of 150-1,000%, an air-permeability of 10-300cm3/cm2.S and high abrasion strength, is resistant to microbial attach and is capable of adsorbing and immobilizing animal and vegetable cells and microorganisms without lowering the physiologically activity. The carrier can be produced by mixing a polyol compound such as a polyether polyol comprising a ≥3-hydric polyhydric alcohol copolymerized with ethylene oxide/propylene oxide with a polyisocyanate compound such as tolylene diisocyanate and water, vigorously agitating the mixture to effect the foaming of the mixture and cutting the obtained porous polyurethane gel into pieces of 4mm cube.