WE CLAIM:
[Claim 1]
A hollow fiber membrane comprising a dense layer that, when a cross-section of the hollow fiber membrane which is perpendicular to a longitudinal direction of the hollow fiber membrane is examined, has pores each having a pore area of 0.28 μm2 or less as the only pores,
wherein the dense layer has been disposed on an outer-surface-side or inner-surface-side of the hollow fiber membrane,
an outer diameter of the hollow fiber membrane is 350 μm or less,
an inner diameter of the hollow fiber membrane is 150 μm or larger,
a membrane thickness of the hollow fiber membrane is 30-90 μm,
a surface of the hollow fiber membrane where the dense layer has been disposed has a plurality of pores, and the plurality of pores have an average pore diameter, as determined through an examination of the surface of the hollow fiber membrane, of 0.3-0.9 μm, and
a ratio (DT/WT) of a thickness of the dense layer (DT) to the membrane thickness of the hollow fiber membrane (WT) is 0.24 or larger. [Claim 2]
The hollow fiber membrane according to claim 1, wherein the dense layer has been disposed in the outer-surface-side of the hollow fiber membrane. [Claim 3]
The hollow fiber membrane according to claim 1 or 2, wherein the surface of the hollow fiber membrane where the dense layer has been disposed has an open pore ratio of 15-45%. [Claim 4]
The hollow fiber membrane according to any one of claims 1 to 3, comprising a polysulfone type polymer and polyvinylpyrrolidone. [Claim 5]
A cartridge for water purifiers comprising the hollow fiber membrane according to any one of claims 1 to 4 mounted therein.