A data transferring system includes a switch and a controller. The switch transfers data from a transmission source to a transmission destination with reference to a table in which a first information and a second information are associated. The controller includes a setter configured to set a tentative table to the switch, the tentative table storing the second information for outputting data, which is matched with the condition represented by the first information, to the controller, an obtainer configured to obtain a route information representing a route between the transmission source and the transmission destination, and an updater configured to update the tentative table to a table in which an outputting destination of data, which is matched with the condition represented by the first information, is changed in accordance with the route information.