The invention relates to a treatment device (1) for a device (2) for producing shock waves (4) that are especially suitable for medical use. Said device comprises a housing (3), in which the device (2) for producing shock waves (4) is arranged, a focusing device (5) in which the housing (3) is inserted and which is sealed from the exterior in a liquid-tight manner by a membrane (10), a bellows structure or the like, a liquid (6) with which the focusing device (5) is filled and which encloses the device (2) for producing shock waves (4), and a conduit (7) through which the liquid (6) can be supplied to and discharged from the focusing device (5). The aim of the invention is to allow gases which naturally occur in the water or gas which is produced by the shock wave production to be chemically bound or to be reconverted to water. For this purpose it is e.g. necessary that as few water molecules as possible escape from the water circuit and are therefore present as reactants for the oxygen molecules for producing water. This aim is achieved by connecting the conduit (7) to a container (11) in which the liquid (6) can be chemically degassed in such a manner that the oxygen molecules (17) present in the liquid (6) react with hydrogen molecules (16) to form water (6) or react with a reducing agent.