A quantum-cryptographic-communication system according to an embodiment includes a key-integrated-management device, quantum-cryptography devices, and key-management-inspection devices. An inspection-target-value-calculating unit calculates an inspection-target value based on quantum-cryptography-device information related to a quantum-cryptography device. An expected-value-calculating unit calculates an expected value based on at least one of wiring information of a QKD link connected to the inspection-target-quantum-cryptography device; weather information of the site installed with the inspection-target-quantum-cryptography device; and the quantum-cryptography-device information. A permissible-value-calculating unit calculates a permissible value based on at least one of the wiring information, the weather information, and the quantum-cryptography-device information. A determining unit determines whether the inspection-target value is within the range of (expected value)−(permissible value) and within the range of (expected value)+(permissible value); and, when the inspection-target value is outside the range of (expected value)−(permissible value) and outside the range of (expected value)+(permissible value), transmits anomaly detection to a key integrated management device.