A gas-adsorbing device (1) includes: a container (2); a gas adsorbent (3) configured to be disposed inside the container (2) so as to adsorb a gas; and an aeration member (4) having a predetermined aeration rate. The gas adsorbent (3) is disposed in a space formed by the container (2) and the aeration member (4). Further, the space is configured to be completely enclosed by the container (2) and the aeration member (4). In this configuration, it is possible to attain a gas-adsorbing device in which it is possible to reduce consumption of the gas adsorbent due to contact with air, even when the gas-adsorbing device is handled in air.