Provided are an aerosol generating device for generating an aerosol by heating a cigarette and a method of generating an aerosol by heating a cigarette. The aerosol generating device may determine whether or not a cigarette is inserted, by using at least one of a cigarette insertion detecting sensor, a temperature detecting sensor configured to detect a temperature change of a heater, or a position detecting sensor configured to detect a position change of a door, without receiving an additional input from a user, and based on whether or not the cigarette is inserted, may control the operation of the heater.
