1. An apparatus for detecting a state of an object, comprising: m (m>=1) electromagnetic field generators 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 devices for identifying and measuring electric field strength which occurs from each of the m electromagnetic field generators; and at least one processor configured to calculate characteristics from time-series data of m×n electric field strength and to identify, by statistical processing, the state of the object from the characteristics and characteristic data collected in each of a plurality of still states of the object, wherein the at least one processor is configured to learn an upper-limit value and a lower-limit value of the electric field strength for each time-series data based on the characteristic data of each still state which has been collected, and wherein the at least one processor is configured to identify the state by the fact that input characteristic data is between the upper-limit value and the lower-limit value of the electric field strength or to identify the state by the fact that input characteristic data is not between the upper-limit value and the lower-limit value of the electric field strength, the input characteristic data being time-series data comprising the amount of fluctuation of the time series data of the m×n electric field strength for a predetermined period.