A position identification server according to the present application includes a storage unit that stores coefficients of parameters of a discriminant function that indicates whether or not a terminal device is located on each floor and a maximum value of pre-measured radio wave strength of each base station on each floor, a communication unit that receives an actual measurement value of radio wave strength of radio waves received by the terminal device from the base station, and a discrimination unit that calculates the parameters of the discriminant function for each floor based on the actual measurement value of radio wave strength received by the communication unit and the maximum value of radio wave strength stored in the storage unit, calculates a solution of the discriminant function for each floor based on the calculated parameters and the coefficients of the parameters stored in the storage unit, and when there are floors where the solution of the discriminant function is greater than or equal to a predetermined value, discriminates that a floor where the solution of the discriminant function is the greatest is a floor where the terminal device is located.