Provided is a canister that makes it possible to reduce production costs. One aspect of the present disclosure is a canister. The canister includes an outer case including a charge port that takes in an evaporated fuel, a purge port that discharges the evaporated fuel, and an atmosphere port open to the atmosphere, an inner case arranged inside the outer case, the inner case having an inner space to which the atmosphere port is connected, a first adsorption chamber arranged in the inner space of the inner case, and a second adsorption chamber arranged between the first adsorption chamber and the atmosphere port in a flow path of the evaporated fuel in the inner space of the inner case. A cross-sectional area perpendicular to a gas flow direction in the second adsorption chamber and a cross-sectional area perpendicular to a gas flow direction in the first adsorption chamber are different.