To reduce a load which is generated when collecting used amount data from an information processor, while preventing a possibility that a user uses the information processor over an upper limit of the used amount from increasing.

A variation threshold is a guide value to determine whether a possibility that the used amount of the information processor reaches an upper limit by the end of a month is large if the user keeps using the processor at a current use frequency. When the used amount is less than the variation threshold (Step S510:Yes), a control part 100 executes a periodic collection, assuming that the possibility that the used amount reaches the upper limit by the end of the month is small even if the user keeps using the processor at the same frequency. On the other hand, when the used amount has reached the variation threshold (Step S510:No), the control part 100 executes a collection as necessary, assuming that the possibility that the used amount reaches the upper limit by the end of the month is large.