CONTROLLER, VEHICLE, STORAGE MEDIUM, AND OPERATION METHOD OF CONTROLLER

A controller (10) includes: a control unit (13) configured to detect, based on information from a sensor mounted on a vehicle (1), a first event indicating that engine oil is discharged from an engine of the vehicle (1), or a second event indicating that the engine is replenished with engine oil; and a storage unit (12) configured to store the result of detection by the control unit (13) as a history of oil change.