A battery replacement assisting system includes a server configured to determine, from a plurality of battery packs including a recycled battery pack, a battery pack serving as a replacement candidate for a battery pack mounted on the vehicle. The server is configured to: acquire a state of deterioration of the battery pack; select a battery pack having a life longer than a period until the planned time from the plurality of battery packs by calculating a distance (life) in which the vehicle can travel until a capacity maintenance ratio of the battery pack reaches a threshold value (Qth); and determine the replacement candidate using a result of the selection and the expense information. The battery replacement assisting system further includes a display configured to notify the user of the replacement candidate determined by the server and the expense information of the replacement candidate.