To provide a communication management system for enabling a predetermined processing based on detection results of movement of an object in a predetermined space, and decision results that the distance to a second communication device is shorter than a predetermined distance, and to provide a communication management method of the communication management system, a communication management device, and a communication device.

A first communication device comprises a first transmitting section transmitting a signal for calculating the distance to a second communication device, a section for detecting the phase difference between a transmitted signal for calculating the distance and a received signal for calculating the distance, and a section for calculating the distance to the second communication device based on the phase difference. The second communication device comprises a second transmitting section transmitting a signal corresponding to the signal for calculating the distance, a section for judging whether the calculated distance is shorter than a predetermined distance or not, and a sensor for detecting movement of an object in a predetermined space wherein a predetermined processing can be carried based on detection results by the sensor and judgment results that the calculated distance is shorter than a predetermined distance.