Provided is a stereo image processing device, with which it is possible to compute disparity with high precision even for an object of a small image region size in a baseline length direction. With this device, an image matching unit (102) acquires a correspondence point of a reference image for a target point of a target image. An image cropping unit (201) extracts first two-dimensional pixel data including the target point from the target image, and extracts second two-dimensional pixel data including the correspondence point from the reference image. An image reconfiguration unit (202) reconfigures the respective first two-dimensional pixel data and second two-dimensional pixel data into first one-dimensional pixel data and second one-dimensional pixel data. A peak position detection unit (104) computes disparity based on the correlation between the first one-dimensional pixel data and the second one-dimensional pixel data.