An occupant detection apparatus includes a first camera and a second camera. The first camera is arranged in a passenger compartment of a vehicle to capture images within a first field of view in the passenger compartment. The second camera is arranged at a different position in the passenger compartment from the first camera to capture images within a second field of view in the passenger compartment. The second field of view is different from the first field of view. Moreover, the first camera is arranged within the second field of view which is the field of view of the second camera. On the other hand, the second camera is arranged within the first field of view which is the field of view of the first camera.