In an apparatus for testing value documents, such as for example bank notes, an area of the bank note is captured from different directions with the help of two optical sensors aligned symmetrically to each other. The measured values supplied by the sensors on the one hand are added up in order to obtain a total measured value which is insensitive to asymmetric effects of the value document, and on the other hand the measured values are subtracted in order to capture exactly these asymmetric effects. In this way with the help of one single apparatus there can be tested authenticity features as well as the quality of the actual state of the value document.