FUEL SAVING DRIVING DIAGNOSTIC EQUIPMENT, IN-VEHICLE SYSTEM, DRIVE CONTROL APPARATUS, AND FUEL SAVING DRIVING DIAGNOSTIC PROGRAM

A fuel-saving driving diagnostic apparatus detects that the vehicle stops based on a vehicle speed indicating a speed of a vehicle, and detects that the vehicle is in an idling state indicating a state in which the vehicle is idled when a number of engine revolutions of the vehicle whose stop is detected is a predetermined threshold or more. The fuel-saving driving diagnostic apparatus determines whether the vehicle in the idling state is in a parking state based on a selection lever and/or a parking brake of the vehicle in the detected idling state. Then the fuel-saving driving diagnostic apparatus diagnoses fuel-saving driving based on an idling parking time for which the parking state of the vehicle is maintained.