▎ 摘　　要

NOVELTY - A gas separation membrane element (1) comprises a central tube (2) for accumulating permeated gas, and a gas separation membrane (3) spirally surrounded by the central tube. The gas separation membrane comprises a porous support film, and separation functional layer on one side of the porous support film and comprising graphene. At least one surface of the porous support film has an arithmetic-mean surface roughness (Ra) of 1.0-10 nm (excluding 10) determined by atomic force microscopy. The ratio of the sum of amount of the aldehyde bond, ketone bond and ether bond in separation functional layer to the amount of carbon-carbon bond in separation functional layer is 0.3-0.8 determined by the X ray photoelectron spectroscopy. USE - Gas separation membrane element used for manufacturing gas (claimed) e.g. light gas such as hydrogen or helium. ADVANTAGE - The gas separation membrane element has high separation selectivity for light gas, and suppresses the occurrence of pinhole defects. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) manufacture of the gas separation membrane element; and (2) manufacture of gas. DESCRIPTION OF DRAWING(S) - The drawing shows a partially-expanded perspective view of the gas separation membrane element. Gas separation membrane element (1) Central tube (2) Gas separation membrane (3) Supply side flow-path material (4) Transparent side flow path material (6)