To provide membrane-forming composition suited to manufacture hollow fiber porous membrane having strength and water permeability at a high level with preferable balance.

A membrane-forming solution contains 10-40 mass% of a polymer component selected from polysulfone and polyether sulfone, 20-60 mass% of a good solvent selected from N-methyl pyrrolidone, dimethyl sulfoxide, dimethyl acetamide, dimethyl formamide, 10-60 mass% of a poor solvent selected from glycols, and 1-25 mass% of polyvinyl pyrrolidone. The hollow fiber porous membrane is formed from the membrane-forming solution.