Abstract: A spiral wound gas permeable membrane module having a hollow mandrel with a plurality of holes, at least one envelope-like gas permeable membrane wrapped spirally around the mandrel, at least one feed water spacer positioned on the outer surfaces of the spirally wrapped envelope-like membrane, and at least one permeation side spacer provided in the envelope-like membrane. The module contains a partition block for blocking the flow of a gas flowing in the mandrel in its longitudinal direction and a flow regulating wall directing the flow of the gas introduced into the envelope-like membrane through the holes aligned on one side of the partition block so that the gas travels in the envelope-like membrane in a spirally outer direction, then returns in a spiral inner direction and flows into the mandrel through the holes aligned on the other side of the partition block.