An aerosol generation device may include a first housing comprising an opening at one side, an inner space for accommodating a cigarette inserted through the opening, and a heater disposed in the inner space; a second housing coupled to other side of the first housing and including a controller; a fastening portion configured to couple the first housing to the second housing; a battery coupled to the second housing; and a case coupled to the second housing for accommodating the second housing, the fastening portion, and the battery therein, wherein the fastening portion is prevented, by the case, from being exposed to outside.