Abstract: The present invention pertains to a device for the flux-free soldering of printed circuit boards guided over the soldering wave of a wave soldering nozzle, wherein the solder is vibrated by means of at least one ultrasonic electrode (sonotrode), the surface of the sonotrode is directly rinsed by the soldering wave, and the printed circuit boards are guided just above the surface of the sonotrode. It is provided that the surface (12, 28) of the sonotrode (5, 21) forms at least a partial area of the surface of the wave former (11, 13) of the wave soldering nozzle (2, 22).