An air treatment device includes: a casing having an inlet through which air is drawn, and an outlet out of which the air drawn through the inlet is blown; a blade configured to adjust a direction of the air blown out of the outlet; and a generator configured to generate an antimicrobial element that sanitizes the blade. The blade has a first surface, and a second surface opposite to the first surface. The blade is shiftable between a first position in which the antimicrobial element is provided to the first surface and a second position in which the antimicrobial element is provided to the second surface.