The present disclosure has an object to provide a technique for enabling a communication state to be confirmed not in a communication building but in a work site, and to provide a technique for enabling correct splicing between optical cables to be confirmed before fusion splicing. The present disclosure is a communication apparatus identification device 4 including an optical fiber bent portion 42 obtained by, when a portion of optical fibers to which communication apparatuses (the OLT 1-2 and the ONU 2) for which appropriateness of connection is to be determined are connected on opposite ends is bent, bending a portion of the optical fibers in a vicinity of a clearance provided between the optical fibers, the clearance having a range in which the communication apparatuses for which appropriateness of connection is to be determined can communicate with each other, and a MAC address analysis unit 43 that analyzes communication light leaked out of the bent portion of the optical fibers in the vicinity of the clearance to acquire identification numbers (MAC addresses) of the communication apparatuses for which appropriateness of connection is to be determined.