To provide a communication device and a communication management system for conducting an efficient communication.

A communication device 20 includes: a demand signal transmission section 25 for transmitting a demand signal for communicating with the targeted equipment; an answer signal receiving section 27 for receiving the answer signal for responding to the demand signal; an elapsed time measuring section 24 for measuring the elapsed time since the transmission time when the demand signal is transmitted; a communication maintenance time information storing part 30 for storing a plurality of communication maintenance time information as the time for maintaining a communication available state for receiving the answer signal; and a communication maintenance time varying section 31 for varying the setting of the communication maintenance time information. The communication maintenance time varying section of the communication device 20 varies the setting of the communication maintenance time information on the basis of the elapsed time.

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