There is provided an apparatus and method for identifying and measuring the electric field strength which occurs from each of RFID tags arranged in a detection target space by a receiver to grasp the state of an object. The apparatus is provided with m (m>=1) electromagnetic field generation means provided near a space, the space being occupied by the object when the object is in a particular state n (n>=1) electric field strength measurement means for identifying and measuring electric field strength which occurs from each of the m electromagnetic field generation means characteristic extraction means for calculating characteristics from m×n time-series data of the electric field strength and state identification means for identifying, by statistical processing, a state from the characteristics and characteristic data in each state for learning.
