A method and device for ultrasound testing of welds is provided. For testing element welds on a body forming a single-piece assembly with these elements, the free end of a poly-articulated robot is fitted with an ultrasound probe which is fitted with an ultrasonic multi-element array transducer; the probe is inserted into the space between two adjacent elements of the assembly; the probe is moved along three-dimensional trajectories along the profile of the element; sectorial electronic scanning is performed in at least two non-parallel testing planes; and ultrasound signals output by the transducer in order to test the welds are processed. The method and device may be applied to welds of blades on the blisk of a bladed disk.