PURPOSE: To obtain a porous hollow yarn membrane having a specific pore structure and having excellent permeation performance and mechanical strength by bringing a vinylidene fluoride resin soln. into contact with liquid exhibiting a specific surface solidifying time.

CONSTITUTION: A polyvinylidene fluoride resin is added to dimethyl sulfoxide and is stirred under heating to 60°C so as to be thoroughly dissolved. Such soln. is discharged from an annular spinning hole, and water-DMFA having nine sec surface solidifying time is used as inside solidifying liquid and water-DMFA mixed liquid having seven sec surface solidifying time is used as outside solidifying liquid, whereby a hollow yarn membrane having 420μ outside diameter and 280μ inside diameter is obtd. The hollow yarn membrane consists of roughly uniform and open cells over the entire section of the membrane and since ≥20μm microvoids do not exist therein, the membrane has high mechanical strength and since average 0.05W5μm pores exist on both inside and outside surface layers, the membrane has an excellent separating characteristic and permeation performance.