A hydrophilic microporous membrane comprising a thermoplastic resin,
having been subjected to hydrophilizing treatment and having a maximum
pore size of 0 to 100 nm, wherein when 3 wt % bovine immunoglobulin
having a monomer ratio of 80 wt % or more is filtered at a constant
pressure of 0.3 MPa, an average permeation rate (liter/m.sup.2/h) for 5
minutes from the start of filtration (briefly referred to as globulin
permeation rate A) satisfies the following formula (1) and an average
permeation rate (liter/m.sup.2/h) for 5 minutes from the time point of 55
minutes after the start of filtration (briefly referred to as globulin
permeation rate B) satisfies the following formula (2): Globulin
permeation rate A>0.0015 .times.maximum pore size (nm).sup.2.75 (1)
Globulin permeation rate B/globulin permeation rate A>0.2 . (2)