A membrane humidifier, comprising: a housing in which a hollow fiber membrane bundle is mounted, the hollow fiber membrane bundle being formed by integrating a plurality of hollow fiber membranes; a potting portion fixing an end portion of the hollow fiber membrane bundle to the housing and coupled to an end portion of the housing so as to hermetically seal the housing; and a sealing member disposed between the housing and the potting portion and hermetically sealing the housing, wherein the sealing member comprises: a solid-state sealing element mounted at the end portion of the housing; and a liquid-state sealing element mounted between the solid-state sealing element, the end portion of the housing and the potting portion so as to couple the solid-state sealing element, the housing and the potting portion resiliently, wherein the solid-state sealing element is made of silicon, acryl rubber, EPDM, or NBR, and the liquid-state sealing element is made of silicon or urethane, wherein the solid-state sealing element comprises: a sealing body mounted at an end of the housing; and a first protruding portion protruded from the sealing body in a length direction of the housing and disposed between an interior circumference of the end portion of the housing and the liquid-state sealing element, and a second protruding portion protruded from the sealing body in the length direction of the housing, wherein the end portion of the housing is positioned between the first protruding portion and the second protruding portion. a housing in which a hollow fiber membrane bundle is mounted, the hollow fiber membrane bundle being formed by integrating a plurality of hollow fiber membranes; a potting portion fixing an end portion of the hollow fiber membrane bundle to the housing and coupled to an end portion of the housing so as to hermetically seal the housing; and a sealing member disposed between the housing and the potting portion and hermetically sealing the housing, wherein a solid-state sealing element mounted at the end portion of the housing; and a liquid-state sealing element mounted between the solid-state sealing element, the end portion of the housing and the potting portion so as to couple the solid-state sealing element, the housing and the potting portion resiliently, wherein the solid-state sealing element is made of silicon, acryl rubber, EPDM, or NBR, and the liquid-state sealing element is made of silicon or urethane, wherein the solid-state sealing element comprises: a sealing body mounted at an end of the housing; and a first protruding portion protruded from the sealing body in a length direction of the housing and disposed between an interior circumference of the end portion of the housing and the liquid-state sealing element, and a sealing body mounted at an end of the housing; and a first protruding portion protruded from the sealing body in a length direction of the housing and disposed between an interior circumference of the end portion of the housing and the liquid-state sealing element, and a second protruding portion protruded from the sealing body in the length direction of the housing, wherein the end portion of the housing is positioned between the first protruding portion and the second protruding portion.