To decide a delivery time when to deliver consumables to a place where an image forming apparatus is installed, accurately.

A communication part 21 acquires a value indicating a toner consumption degree and a value indicating operation conditions of an image forming apparatus 3 from the image forming apparatus 3. An estimated consumption specification part 22 specifies an estimated current toner consumption on the basis of the value indicating toner consumption and the value indicating the operation condition acquired from the image forming apparatus. A prediction part 23 calculates an estimated toner replacement date on the basis of the estimated toner consumption. A delivery instruction part 24 sets a toner arrival date by dating back to satisfy the same toner NG quantity as before from the estimated toner replacement date, and decides a toner delivery date by dating back by the number of toner delivery days from the toner arrival date, to issue a toner delivery instruction.