To provide a method and device for discriminating position information capable of precisely discriminating the position information of a mobile terminal in line with the actual environment.

A device 20 for discriminating the position information includes: a discrimination value calculation unit (a discriminant generation part 207, a control part 208) which calculates a discrimination value depending on the amount of variation from a predetermined value of reception power of a radio signal received by a mobile terminal 10 from a base station, and the duration for the amount of variation; and a determination unit (the control part 208) which determines whether the mobile terminal 10 is located inside or outside a building in comparison between the discrimination value and the prescribed value.