An RF tag includes a sensor for detecting a change in an environment near the RF tag, a storage section for storing identifier information uniquely assigned to each RF tag to identify the RF tag, and a controller for controlling the sensor and the storage section. A reader-writer includes a sensor value requesting section for requesting, with respect to the identifier information, a sensor value detected by the sensor. When the environmental information changes, the reader-writer identifies an object according to the sensor value sent from the RF tag including the identifier information as a response to the reader-writer. It is therefore possible, using an information management system, an information management method, a program, and a recording medium, to recognize an object including a particular tag.