Provided is a charging method capable of offering a user an incentive to use a particle generation factor determining system. In the particle generation factor determining system including a user interface device 11 through which a user inputs a particle map and a server 13, the server 13 calculates accuracy of each of multiple particle generation factors based on the particle map; the user interface device 11 displays the calculated accuracy or a title of generation-factor-relevant information 27 on each particle generation factor corresponding to this accuracy; the server 13 provides the generation-factor-relevant information 27 to the user interface device 11; a charged fee for providing particle generation-factor-relevant information 27 is determined based on accuracy of a particle generation factor corresponding to the provided generation-factor-relevant information 27.