Gas separation device

A gas separation device (10) is provided with: a first separation module (1a) for recovering a specific gas component at a first recovery rate and a second separation module (1b) for separating the specific gas component at a second recovery rate; a second separation module (1b) that recovers a specific gas component at a second recovery rate lower than the first recovery rate; a first supply line (L1a) for supplying a starting material gas containing a specific gas component at a predetermined concentration or more to the first separation module (1a); a second supply line (L2a, L1b) for recovering, from the first separation module (1a), the permeated gas that has passed through the separation membrane (M) and supplying the permeated gas to the second separation module (1b); and third supply lines (L3b, L1a) for recovering the permeated gas that has passed through the separation membrane (M) from the second separation module (1b) and supplying the permeated gas to the first separation module (1a). 本发明提供一种气体分离