The invention relates to a method and device for ascertaining an edge layer characteristic of a component (12), in particular a component (12) for an aircraft engine. In the method, a reference body (22) with a known edge layer characteristic is arranged on the surface of the component (12). An ultrasonic wave (18) is introduced into the surfaces of the component (12) and the reference object (22) by an ultrasonic transmitter (16). An ultrasonic wave (18) resulting from the exchange between the component (12) and the reference body (22) is detected by an ultrasonic detector (20), and an edge layer characteristic of the component (12) is ascertained by an ascertaining device (28) using a difference between the generated ultrasonic wave (18) and the resulting ultrasonic wave (18).