Proximity Detection System

Provided is a proximity detection system which is capable of changing a level of alarm depending on a distance between a worker and an apparatus, and setting an alarm-generating distance in an apparatus-side unit. The proximity detection system comprises a magnetic field detecting function-equipped RFID tag attachable to a worker, and a distance detection control unit installable in a self-propelled apparatus. The magnetic field detecting function-equipped RFID tag is configured to be selectively set between a plurality of levels of magnetic field detecting sensitivity, and comprises means to intermittently transmit setup magnetic field detecting sensitivity data and magnetic field detection data. The distance detection control unit is configured to output different levels of alarm according to the data received from the RFID tag.