Abstract: An apparatus for generating high frequency shock waves having a truncated ellipsoidal reflector is provided. The apparatus has a cavity which constitutes a chamber for reflecting shock waves, the chamber being filled with a dielectric liquid such as water or oil. The apparatus also has a shock wave generator device which generally has two electrodes and a source for selectively and substantially instantaneously providing an electric voltage to the electrodes. The equipotential screen is fast with the ellipsoidal reflector and is grounded by the support formed by the ellipsoidal reflector. This equipotential screen limits electric leakage and thus renders the apparatus safer in operation for destroying targets such as tissues, biliary concretions, kidney stones, etc.