A position estimation system uses an information terminal and has an improved position accuracy. To achieve the purpose, this position estimation system is provided with a first information terminal having a function to transmit a wireless signal associated with identification information and a second information terminal having a function to measure a reception intensity of the wireless signal, and is configured in such a way that: the reception intensity of the wireless signal transmitted by the first information terminal is measured by the second information terminal; at least one of the first information terminal and the second information terminal measures a movement distance; and at least one of the first information terminal and the second information terminal estimates a relative positional relationship between the first information terminal and the second information terminal from a change in the reception intensity of the wireless signal with respect to the movement distance.