An object detection apparatus in a vehicle is provided. The object detection apparatus includes one or more sensors configured to detect at least one object located on at least three rows of seats in the vehicle, the one or more sensors being positioned on a ceiling of the vehicle. The object detection apparatus further includes a circuit configured to determine whether or not the at least one object detected is a living-object. A number of the one or more sensors is less than a number of the at least three rows of seats.