An aerosol generating device according to an embodiment includes a heater generating an aerosol by heating an aerosol generating substrate; a controller for controlling power supplied to the heater; at least one detachable element that is attachable to and detachable from an inner space or an outer space of the aerosol generating device; and a plurality of geomagnetic sensors for detecting changes in the strength of an internal magnetic field of the aerosol generating device, wherein the controller detects detachment of the detachable element based on a detection result from at least one of the plurality of geomagnetic sensors.