An elongate aerosol-generating device (100, 1000) has at least a portion of its transverse external cross-section defined by a shape having at least 5 sides. The device has an external cross-section having an outer circumcircle having a diameter of between 10 mm and 20 mm, the shape having at least five corners joined by curves. The cross-sectional shape of the device prevents rolling. The aerosol-generating device may comprise a substrate receiving cavity (302) adapted to receive an aerosol-forming substrate to form an aerosol, a heating element, and a power supply (506) adapted to provide power to the heating element.
