Abstract: A position-monitoring device for persons in tunnel systems having an evaluation device. Reliable determination of the position of persons in the tunnel system is achieved because a locally distributed arrangement of wireless transceiver units is installed in the tunnel system, at fixed anchoring points known to the evaluation device, in the spaces to be monitored. Persons are equipped with mobile sensors. Transceiver units have wireless data-transmission interfaces via which, on one hand, can be placed in a wireless data-transmitting connection to the mobile and, on the other hand, can be placed in a wire-bound or wireless data-transmitting connection to the evaluation device. Programs with which the position of the persons can be determined on the basis of detection data of the transceiver units are stored in the evaluation device.