An aerosol generation device includes a case into which a cigarette is to be inserted; a protrusion pipe of a hollow shape protruding from one end portion of the case and having an opening; a heater installed in the case such that an end portion thereof is positioned inside the protrusion pipe, and configured to generate heat when an electric signal is applied thereto; and a heater fixing portion installed inside the protrusion pipe to support the heater and comprising a round surface that extends from an inner side surface of the protrusion pipe.