PURPOSE: To produce a porous hollow fiber membrane having a smooth inner surface and a round cross-sectional shape and free from a flaw such as a pinhole from an extremely low viscosity solution.

CONSTITUTION: In spinning a porous hollow fiber membrane having a smooth inner surface and a round cross-sectional shape and free from a flaw such as a pinhole from a low viscosity solution of a polymer, the ratio of the linear velocity of the injection liquid discharged from the center pipe of an annular cap and the linear velocity of the polymer solution discharged from an annular orifice is set to 0.85-2.0 and the ratio of the taking-up speed of hollow fiber in a coagulation bath and the linear velocity of the polymer solution discharged from the annular orifice, that is, a draft ratio is set to 0.7-1.1.