CONTROLLER AND CONTROL METHOD OF RIDER SUPPORT SYSTEM

The present invention provides a controller and a control method that suitably assist a rider in driving a motorcycle. A controller for a rider support system has an acquisition unit and an execution unit. The acquisition unit acquires a surrounding environment information while the motorcycle () travels. The surrounding environment information is information about an environment surrounding the motorcycle. The execution unit causes the motorcycle () to execute an adaptive cruise control operation based on the surrounding environment information. The execution unit causes the motorcycle () to execute: a first operation as the adaptive cruise control operation when a group ride mode in which the motorcycle () travels together with at least one motorcycle in a group is inoperable; and a second operation as the adaptive cruise control operation when the group ride mode is operable, the second operation is different from the first operation. The execution unit causes a notification device to provide different notifications in the first operation and the second operation respectively, the notification is given to the rider.