Disclosed are: a membrane humidifier cartridge capable of preventing a hollow fiber membrane, accommodated in the cartridge, from being damaged by fluid; and a fuel cell membrane humidifier comprising the membrane humidifier cartridge. The disclosed membrane humidifier cartridge comprises: an inner case in which a hollow fiber membrane through which a first fluid flows is accommodated; a potting part for fixing the end of the hollow fiber membrane; a first mesh hole part into which a second fluid flows and which protrudes from one side of the inner case; and a second mesh hole part from which the second fluid having flowed through the first mesh hole part is discharged after exchanging moisture with the first fluid through the hollow fiber membrane, and which protrudes from the other side of the inner case.