The invention relates to a method for generating ultrasonic waves focused on a focal zone (5) in order to carry out biological lesions, comprising the activation of a plurality of ultrasonic transducer elements (3). According to the invention: a target zone, in which homogenization of the supply of energy of the ultrasonic waves emitted by the ultrasonic transducer elements is desired, is chosen, the focusing effect and the acoustic attenuations of the ultrasonic waves on their path between the target zone and the ultrasonic transducer elements (3) are determined, the focusing effect and the acoustic attenuations of the ultrasonic waves are compensated, with ultrasonic transducer elements (3) at least some of which have non-identical emission surfaces such that in the target zone, the supply of energy of the ultrasonic waves emitted by the different ultrasonic transducer elements (3) is more or less identical.