An asymmetric hollow
fiber gas separation membrane obtained by subjecting an asymmetric hollow
fiber polyimide membrane to a heat treatment having a
maximum temperature of from 350 to 450° C., wherein the asymmetric hollow
fiber polyimide membrane is formed with a
polyimide essentially having a repeating unit represented by a general formula (1);is excellent in a
solvent resistance and a
thermal stability, and as well has such a
mechanical strength that a tensile elongation at break is not less than 10% as a
hollow fiber membrane. In the general formula (1), 20 to 80 mol % of A is a tetravalent unit based on a
biphenyl structure represented by formula (2), 20 to 80 mol % of A is a tetravalent unit based on a diphenylhexafluoropropane structure represented by formula (3), and 0 to 30 mol % of A is a tetravalent unit based on a phenyl structure represented by formula (4); and in the general formula (1), 30 to 70 mol % of R is a
divalent unit represented by formula (5) and / or formula (6), and 30 to 70 mol % of R is a
divalent unit having one or two other aromatic rings than formula (5) or (6),wherein, R1 and R2 are a
hydrogen atom or an
organic group, and n is 0, 1 or 2,wherein, R1 and R2 are a
hydrogen atom or an
organic group, X is —CH2— or —CO—, and n is 0, 1 or 2.