The present invention relates to a gasket assembly which can be manufactured with increased productivity and can dramatically reduce maintenance costs, and a fuel cell membrane humidifier comprising same. According to an embodiment of the present invention, the gasket assembly is for the fuel cell membrane humidifier which comprises: a mid-case; a cap fastened with the mid-case; and at least one cartridge arranged in the mid-case and receiving a plurality of hollow fiber membranes. The gasket assembly comprises: a sub-case which is formed in a shape surrounding the end portion of the cartridge and has a first hole, in which the end portion of the cartridge is inserted, formed therein; and a gasket including a packing portion which has a second hole in which the sub-case is inserted and absorbs vibrations of the cartridge in the horizontal direction by coming into close contact with the outer circumference of the sub-case inserted in the second hole, an edge portion that is connected to the packing portion and interposed in a space formed by a groove formed in the end portion of the mid-case and the end portion of the cap, and a damping portion that is formed on the outer circumference of the sub-case and is restricted from moving in the vertical direction by the packing portion to absorb the vibrations of the cartridge in the vertical direction.