An information system for recharging a mobile body powered by electric energy comprises an energy request amount acquiring unit, which acquires information related to an energy request amount based onthe location of the mobile body; an energy supply speed acquiring unit, which acquires information related to the energy supply speed of a supply candidate which can supply the energy request amountbased on (i) information related to a suppliable energy amount and (ii) information related to an energy supply speed of each of one or more supply candidates which can supply the energy; and an energy supply time period determining unit, which determines a supply time period based on the request amount and the information related to the supply speed of each of the supply candidates which can supply the energy request amount.