There is provided a heater (101) for heating an aerosol forming substrate. The heater comprises a plurality of elongate heating elements (107) arranged in an elongate array. The elongate array has a support end with a first dimension a heating end with a second dimension and a middle portion with a third dimension. The array is arranged to heat the substrate to form an aerosol. The third dimension is greater than the first dimension and greater than the second dimension. There is also provided an electrically heated aerosol generating system including such a heater.
