Based on an idea that there is a correlation between the number of mobile terminals 300 detected inside a facility (that is, a detected terminal count) and visitors of the facility, the number of users using the facility (that is, a crowd condition of the facility) is estimated using a WiFi function provided in the mobile terminals 300. Consequently, the crowd condition of the facility can simply be estimated while costs are suppressed to be low, compared to conventional methods in which, e.g., infrared modules or Web cameras are provided at entrances/exits of a facility to estimate a crowd condition.