System and method for assisting charging to use of accelerator unit

A charging assistant system that assists charging for use of an accelerator unit, which is one or more accelerators, includes an operation amount obtaining unit, an acceleration rate estimation unit, and a use fee determination unit. For each of one or more commands input into the accelerator unit, the operation amount obtaining unit obtains the amount of operation related to execution of the command from a response output from the accelerator unit for the command. For the one or more commands input into the accelerator unit, the acceleration rate estimation unit estimates an acceleration rate on the basis of command execution time that is time required for processing of the one or more commands, and one or more amounts of operation obtained for the one or more commands respectively. The use fee determination unit determines a use fee of the accelerator unit on the basis of the estimated acceleration rate.