A method for inspecting a part by a non-destructive ultrasound inspection, the part is immersed in an acoustic wave conducting medium and an incident ultrasound wave having a wide beam of section Σ is emitted into the ultrasound-conducting medium towards the part. The characteristics of the waves reflected by faces of the part to be inspected are measured on at least a small section σ, the characteristic dimensions of which are substantially less than those of the section Σ. The location of the section or sections σ is determined such that, despite the possible variations of the position of the part and the relative slopes of its faces, the section σ is always located in the volumes passed through by the reflected waves, for example substantially in an area close to the axis of the incident beam when the incident beam is controlled to be oriented substantially in a direction perpendicular to a face of the part.