To provide a means for increasing safety of mountain climbers and reducing efforts of those who engage in monitoring climbers carrying communicating means to be used in an emergency and allows easy positioning of climbers by referring to positional information received from a mobile terminal carried by the climbers and recorded in a monitor center and the like even in a situation when communication is difficult because of the state of emergency including an accident.

Monitoring is executed with a mobile terminal, such as a portable telephone, PHS(Personal Handy Phone System) and the like, that converts positional information and identification signals of its own to radio signals for transmission by means for obtaining its own positional information with GSP receiving means and storing means for storing its own identifying signals; mobile communication channel including a radio base station that receives radio signals from mobile communication terminals or controls communication; and a monitoring center that monitors mobile communication terminals.