There is provided an image processing device including: an image acquisition unit for acquiring a first image including, as a subject, a first region captured by a first camera which captures an image from a first altitude toward a direction of an altitude lower than the first altitude, and a second image including, as a subject, the first region captured by a second camera which captures an image from a second altitude toward a direction of an altitude lower than the second altitude; and a flying object detection unit for detecting a flying object at an altitude lower than the first altitude and the second altitude, based on a difference between the first region in the first image and the first region in the second image.