HUMIDIFIER

A humidifier includes a mid-casing member having therein a space and having a first hole formed at one side thereof, and a second hole formed at the other side thereof, a cartridge part including a plurality of cartridge members accommodated in the mid-casing member and disposed to be spaced apart from one another in a first direction D, and humidification membrane members accommodated in the cartridge members, in which two opposite ends of the plurality of cartridge members based on the first direction D are positioned within a width of the first hole in the first direction D.