1. An object detection device comprising: a candidate object selection unit suitable for converting a stereo image transmitted from moving cameras into a disparity image, and selecting pixels having a disparity value greater than a threshold value in histogram of the disparity image as candidate objects; a global motion estimation unit suitable for calculating motion vectors for coordinates of the stereo image through optical flow, and estimating global motions representing movement of the moving cameras through sample data extracted from the motion vectors; and an object determination unit suitable for extracting outliers from difference between global motion vectors calculated through the global motions estimated by the global motion estimation unit and the motion vectors calculated through the optical flow, and detecting a candidate object having a ratio of outliers greater than a predetermined ratio among the candidate objects selected by the candidate object selection unit as a moving object.