Abstract: An apparatus for applying adhesive onto a joining surface of an adherend is provided which eliminates laborious cleaning and surface-pretreatment steps prior to application of the adhesive onto the substrate surface. Sufficient adhesive bond quality can thereby be ensured even when the joining surface is unavoidably contaminated or recontaminated. The apparatus comprises a sonotrode and a conduit for the delivery of adhesive arranged in the sonotrode. The conduit comprises an adhesive outlet opening that is arranged in the region of the exposed head end of the sonotrode. The sonotrode is configured so that in operation, the vibrations of the sonotrode are transferred to the adhesive emerging from the adhesive outlet opening.