This invention provides a heating unit and its construction, in which ceramic plates are fastened which have a positive temperature coefficient in terms of electrical resistance. A heating unit comprises two electrode plates and ceramic plates which have a positive temperature coefficient in terms of electrical resistance. This heating unit is characterised in that the two electrode plates are of annular shape and in that the PTC ceramic plates are radially arranged, the two ends or the two radial ends of each PTC ceramic plate being firmly attached to one each of the two electrodes.
