Abstract: The invention relates to banknote verification devices that work using transmitted light. The claimed device has the technical result of uniformly illuminating the banknote that is being tested. The device comprises radiators (1), radiation receivers (3) situated on the opposite side of a banknote (2), and a light guide (4) which is situated between the radiators and the tested banknote and which is designed in the form of a tetrahedral prism with a trapezoidal base. One of the parallel side faces of the light guide (4) used as a radiation inlet face is oriented towards the radiators, while the opposite outlet face is oriented towards the surface of the banknote, all the other faces being light reflecting. The radiators (1) are disposed along the inlet face of the light guide (4) with equal intervals therebetween so that the sections of the outlet surface illuminated by adjacent radiators overlap.