An information processing system (40, 70), comprising: a request amount acquiring unit to acquire information related to a request amount of electric power or electricity for driving a mobile body, the request amount determined based on a location of the mobile body that uses the electric power or electricity; a supply speed acquiring unit (46, 72) to acquire a value of power feeding speed or charging efficiency per combination of a specification of a battery of the mobile body and a specification of a power feeding apparatus of each of one or more supply candidates which can supply the request amount of the electric power or electricity, the supply speed acquiring unit configured to acquire the value based on (i) information related to a suppliable amount of the electric power or electricity and (ii) information related to the power feeding speed or charging efficiency of each of the one or more supply candidates; and a supply time period determining unit to determine a supply time period, which is a period from a time at which the supply candidate starts to provide the electric power or electricity to a time at which the request amount of the electric power or electricity is provided, based on the information related to the request amount acquired by the request amount acquiring unit and the value of power feeding speed or charging efficiency, acquired by the supply speed acquiring unit (46, 72), with respect to each of the supply candidates which can supply the request amount of the electric power or electricity, wherein each of the one or more supply candidates includes: (i) at least one of a power generating apparatus, a power storage apparatus, and a charging apparatus mounted on a mobile body, or (ii) at least one of a mobile power generating apparatus, a mobile power storage apparatus, and a mobile charging apparatus. a request amount acquiring unit to acquire information related to a request amount of electric power or electricity for driving a mobile body, the request amount determined based on a location of the mobile body that uses the electric power or electricity; a supply speed acquiring unit (46, 72) to acquire a value of power feeding speed or charging efficiency per combination of a specification of a battery of the mobile body and a specification of a power feeding apparatus of each of one or more supply candidates which can supply the request amount of the electric power or electricity, the supply speed acquiring unit configured to acquire the value based on (i) information related to a suppliable amount of the electric power or electricity and (ii) information related to the power feeding speed or charging efficiency of each of the one or more supply candidates; and a supply time period determining unit to determine a supply time period, which is a period from a time at which the supply candidate starts to provide the electric power or electricity to a time at which the request amount of the electric power or electricity is provided, based on the information related to the request amount acquired by the request amount acquiring unit and the value of power feeding speed or charging efficiency, acquired by the supply speed acquiring unit (46, 72), with respect to each of the supply candidates which can supply the request amount of the electric power or electricity, wherein each of the one or more supply candidates includes: (i) at least one of a power generating apparatus, a power storage apparatus, and a charging apparatus mounted on a mobile body, or (ii) at least one of a mobile power generating apparatus, a mobile power storage apparatus, and a mobile charging apparatus. (i) at least one of a power generating apparatus, a power storage apparatus, and a charging apparatus mounted on a mobile body, or (ii) at least one of a mobile power generating apparatus, a mobile power storage apparatus, and a mobile charging apparatus.