An air treatment device is disclosed. The air treatment device according to one embodiment of the present invention comprises: a first air passage part of which one side is connected with at least one contamination space; a first air suction part for enabling the contaminated air within the contamination space to flow into the first air passage part; and a first air treatment part including: a partition formed inside a toilet water tank; at least one of through-holes, which is formed in the partition, connected with the other side of the first air passage part, and connected with a space inside the partition; and an air discharging part for discharging the contaminated air into the inside of the partition.