Patent ID: 8197688

Claim:
A hollow fiber membrane module comprising: a membrane bundle of a plurality of hollow fiber membranes; a cylindrical body housing the membrane bundle; a raw water outflow-side fixing portion in which a raw water outflow-side end of the membrane bundle is fixed to the cylindrical body; a raw water outflow nozzle for allowing raw water to flow out from a vicinity of the raw water outflow-side fixing portion; a raw water inflow-side fixing portion in which a raw water inflow-side end of the membrane bundle is fixed to the cylindrical body; and a raw water inflow nozzle for allowing raw water to flow in from a vicinity of the raw water inflow-side fixing portion, the raw water supplied into the cylindrical body being allowed to permeate from an outside into an inside of each hollow fiber membrane, wherein the raw water outflow-side fixing portion has at least one groove in a portion of the raw water outflow-side fixing portion which is to be in contact with the raw water, wherein at least part of the at least one groove of the raw water outflow-side fixing portion communicates with the raw water outflow nozzle, the at least one groove having a depth of 5 to 20 mm, a bottom of the at least one groove having an area which is 5 to 25% of a cross-sectional area of the raw water outflow-side fixing portion, and wherein the raw water inflow-side fixing portion includes, in a portion of the raw water inflow-side fixing portion which is to be in contact with the raw water, a plurality of through-slits and a plurality of fixed membrane bundle portions extending approximately parallel to the through-slits, wherein an aperture ratio of the through-slits is 5 to 25% of a cross-sectional area of the raw water inflow-side fixing portion, the through-slits having a width of 1 to 8 mm.