The present invention relates to a method and device for uniformly heating products, the products (8, 15) being heated by a high-frequency electromagnetic alternating field. The method and the device are characterised in that the high-frequency electromagnetic alternating field for heating the products (8, 15) is produced by means of a semiconductor generator (4). By using a semiconductor generator (4), temperature fluctuations in the event of fluctuating load due to the transport of the products (8, 15) through the heating volume (7, 17) are reduced, so that a more uniform temperature of the products (8, 15) can be achieved in the heating process.