A canister that adsorbs and desorbs fuel vapor generated in a fuel tank of a vehicle includes a housing and at least one expansion inhibitor. The housing is in a form of a cylinder configured to be filled with activated carbon. The housing includes a filled portion which is an area in the housing filled with the activated carbon; an unfilled portion which is an area in the housing not filled with the activated carbon; a boundary portion that defines a boundary between the filled portion and the unfilled portion; and a center portion which is situated at the axial center of the filled portion. The at least one expansion inhibitor inhibits an expansion of the boundary portion in an outward direction from being greater than an expansion of the center portion in the outward direction.