A tag (1) can be split into a tag A (1-a), a tag B (1-b), and a tag C (1-c). The tag A includes a memory portion (A31). The tag B includes a memory portion (B32). In the tag C are included a memory portion (C33), an input/output interface portion (34), and a control portion (35). The input/output interface portion (34) forms an interface for exchanging data with an outside reader/writer device (not shown). The control portion (35) control functions of a tag upon receiving a request input from the input/output interface portion (34). Further, a split line (36) is provided between the tag A and tag B, and both tags can be split at this line. A split line (37) is provided between the tag B and tag C, enabling both tags to be split at this line, which makes tag data tampering difficult and work simpler.