An API management device includes: a reception unit configured to receive a selection of a charging condition when using an API; a receiver configured to receive a request for the API from the application; a transmitter configured to transmit a response according to the request to the application; and a history storage configured to store a history of the request for the API and the response for each of the applications that use the API. A charging management device includes: a charging condition storage configured to store the charging condition received by the reception unit for each of the applications that use the API when using the API; an acquisition unit configured to acquire information on the history from the history storage; and a determination unit configured to determine a charge value for the application that uses the API based on the charging condition and the information on the history.