A multichannel spark-gap with multiple intervals for use in pulsed high-power generators of the LTD family. The spark-gap includes a sealed chamber, two discharge electrodes connected to electrical connecting elements, and a number of intermediate electrodes arranged uniformly inside the sealed chamber. One of the intermediate electrodes is called triggering electrode and is connected to triggering elements enabling the spark-gap to be fired. The triggering electrode further includes integral pipes enabling a gas to be distributed inside the chamber, so as to improve the voltage strength of the spark-gap. The spark-gap is characterised in that the negative discharge electrode includes a corona effect device equipped with needles whereof the geometry is adapted to compensate for the differences in shape between the negative discharge electrode and the immediately adjacent intermediate electrode so as to ensure a homogeneous distribution of the potentials inside the sealed chamber.