An object detection apparatus includes an input port that receives information on a plurality of objects in surroundings of a vehicle and information on a traffic environment of the vehicle, the plurality of objects being detected by a sensor installed on the vehicle, a controller that determines, based on the information on the plurality of objects and the information on the traffic environment, priority for each of the plurality of objects and determines first information based on the priority in a case where the total amount of information on the plurality of objects is greater than a determined value, the first information being information on part of the plurality of objects, and an output port that outputs the first information to an in-vehicle apparatus that controls the vehicle.