The invention relates to an atomizer (26) for an electronic smoking device, to a cartomizer with an atomizer (26) and to an electronic smoking device with an atomizer (26). In order to improve atomizing efficiency, the atomizer (26) comprises a heating coil (28) made of a heating wire (40) with a first section (44) and a second section (46), wherein the first section (44) comprises an electrical resistance per length unit that differs from an electrical resistance per length unit of the second section (46).