An ultrasound device for checking the quality of a composite material structure during the production cycle. Preferably, the device is incorporated into a production tooling performing the LRI process in which the composite material structure is placed between two molds during the production cycle. A layer of piezoelectric material is deposited on the face of one of the molds, opposite the face which is in contact with the structure. One face of an electrically insulating flexible material film is placed against the outer face of the piezoelectric material layer. The face of the film further includes conductive pads in contact with the piezoelectric material layer. Each pad is energized by electric voltage applied by a conductive strip. Each pad forms an independent ultrasonic transducer with the region of the piezoelectric material layer opposite of its placement.