HUMIDIFIER

A water recovery device that allows a first gas to flow inside hollow fiber membranes and a second gas to flow outside the hollow fiber membranes, and that exchanges moisture between the first gas and the second gas. The water recovery device includes: a hollow fiber membrane bundle in which plural pieces of the hollow fiber membranes are bundled; a storage case that is open at both ends and houses the hollow fiber membrane bundle thereinside; a housing that includes an introduction hole and a discharge hole of the first gas and an introduction hole and a discharge hole of the second gas, and houses the storage case thereinside; a storage case seal groove which is formed on an outer peripheral surface of one end side of the storage case and to which a seal member is attached for sealing a gap between the outer peripheral surface of one end side of the storage case and an inner peripheral surface of the housing; and a housing seal groove which is formed on the inner peripheral surface of the housing and to which a seal member is attached for sealing a gap between the inner peripheral surface of the housing and an outer peripheral surface of the other end side of the storage case.