CONTROLLER AND CONTROL METHOD

The present disclosure provides a controller and a control method that execute an adaptive cruise control appropriately in a group riding. According to the present disclosure, an execution section () of a controller () executes an adaptive cruise control based on a surrounding environment information that is information about a surrounding environment of the motorcycle (). The execution section (), in the adaptive cruise control, controls a speed of the motorcycle () automatically regardless of an accelerating/decelerating operation by a rider of the motorcycle () and executes a distance maintenance control to keep a distance between the motorcycle () and a target vehicle at a target distance. An identification section () of the controller () identifies a first convoy including the motorcycle () in a group riding in which the motorcycle () travels in a group of a plurality of motorcycles () forming at least the first convoy and a second convoy separated from each other. The execution section () executes the adaptive cruise control based on a first travel state information about a travel state of a second motorcycle, the second motorcycle is one of the plurality of motorcycles () and is in the second convoy.