A heater assembly includes a heater extending to correspond to at least a part of a length of a cigarette and comprising one end to be inserted into the cigarette and configured to generate heat when electricity is applied; a first cover coupled to the heater to maintain a position with respect to the heater and comprising one surface that faces toward the end of the heater and extends outward from the heater; and a second cover coupled to another end of the heater and supporting another surface of the first cover facing toward the other end of the heater.