Abstract: To measure the leakage rate in hollow bodies, the throughflow rate of the air flowing into the leaky hollow body is automatically measured and indicated numerically at a given test pressure. This is achieved by feeding fluid from a prechamber filled with fluid under measuring pressure to two measuring chambers (4,5) equipped with a testpiece and reference housing and having an identical cavity. The pressure decrease in a prechamber (1) is thereupon evaluated as a measure of the accessible volume in the two measuring chambers (4,5) and is compared with the volume given as permissible. If the measured accessible volume is higher than the volume given by the size of the chamber, the testpiece is qualified as highly leaky. If the volumes in the two chambers (4,5) correspond to one another, the chambers (4,5) are separated from the prechamber and the pressure difference between the chambers (4,5) and its trend in time are detected, in order to determine from this a measure of the tightness of the testpiece.