An apparatus for heating gases, particularly air, with a heating unit having a mounting part, at least one PTC component, at least one insulating frame part surrounding the latter, at least one contact plate and at least one insulating support. The PTC component is surrounded by the frame part being inserted in the mounting part and on at least one flat side rests a contact plate and is covered by an insulating support. Heat emission lamellas are mounted in a clamping manner on the heating unit to ensure an effective heat emission to the surrounding air or gas.