In a device for generating plasma in a vacuum chamber (9) with the aid of alternating electromagnetic fields, at least one rod-shaped conductor (7) is guided inside of a tube (16) made of insulating material through the vacuum chamber (9), the insulating tube (16) is held at its ends in one or in the opposing walls (6;17,17a) of the vacuum chamber (9) and is sealed off, wherein one or both ends of the rod-shaped conductor (7) are connected to a generator (18,19), wherein one or both ends of the rod-shaped conductor (7) are surrounded by outer conductors (20,21), each extending from the generator (18,19) to the respective inside wall surface (22,22a) of the vacuum chamber (9), wherein, in the area of the wall passages, the rod-shaped conductor (7) connected to the sources (18,19) and the outer conductors (20,21) surrounding it are each provided with a branch constituting a bypass (23,24), wherein a second rod-shaped conductor (26) extending into or through the vacuum chamber (9) surrounded by a second insulating tube (25), is connected to each of these bypasses (23,24), wherein the length of each bypass amounts to .lambda./2.