A power charging station administration device administrates available time slot information and installation site information set by an administrator of an in-vehicle battery charger, that is, the available time slot information representing time slots at which the in-vehicle battery charger is available and the installation site information representing the installation site of the in-vehicle battery charger using an administration. An information publication unit publishes the available time slot information and the installation site information administrated by the administration unit on a homepage. An occupant of a vehicle A other than the administrator of the in-vehicle battery charger can use the in-vehicle battery charger by verifying the published information during time slots at which the in-vehicle battery charger is available.