Heating device

The device (20) has a housing (21) comprising a fluid channel (22) with a fluid inlet (23) and a fluid outlet (24). An alternating magnetic field generating element (29) i.e. coil, is arranged in the housing. The element is sealed from the channel by a wall (30), and metallic surface heating elements (32, 33) are heated by alternating magnetic field. The heating elements are arranged in the channel, where fluid medium flows through the heating elements. The field generating element is designed as a hollow-cylindrical element, where the wall is made from magnetic field transparent material.