The purpose of the present invention is to reduce the introduction cost of an indoor positioning system using inaudible sound. A positioning system according to one embodiment includes a first acquisition unit, a second acquisition unit, and a positioning unit. The first acquisition unit acquires a reception log indicating that a fixed receiver receives signal source-specific inaudible sounds from multiple signal sources. The second acquisition unit acquires, from a storage unit, signal source information on multiple signal sources corresponding to a fixed receiver installed near a mobile terminal. Here, the signal source information contains information for identifying a signal source from inaudible sound, the transmission timing of inaudible sound at the signal source, and the location of the signal source.