A stereo image processing device that processes a stereo image, comprising: a first camera and a second camera adapted to image an imaged target, wherein the first camera includes a first lens adapted to converge light from the imaged target and a first sensor adapted to receive light transmitted through the first lens, wherein the second camera includes a second lens adapted to converge light from the imaged target and a second sensor adapted to receive light transmitted through the second lens, wherein the first camera and the second camera are placed away from each other, wherein a center of the first sensor is shifted from an optical axis of the first lens by a first shift distance (d) away from the second camera in a first direction parallel to a straight line connecting a center of the first lens and a center of the second lens, and wherein a center of the second sensor is shifted from an optical axis of the second lens by a second shift distance (d) away from the first camera in the first direction, characterized in that, the first shift distance (d) is larger than D × f1 × L / { (L-f1)}, and the second shift distance (d) is larger than D × f2 × L / { (L-f2)}, where f1 is a focal length of the first lens, f2 is a focal length of the second lens, D is a distance between a center of the first lens and a center of the second lens, and L is a maximum distance allowing the acquisition of a signal that has a sufficient accuracy for the first and the second sensors (CSL, CSR) to calculate the distance to the imaged target, and wherein the first lens and the second lens both have a characteristic approximately same as that of an fθ lens at areas with small viewing angle θ, whereas the image height is smaller than that of an fΘ lens at areas with large viewing angle Θ, such that the increment of the image height is gradually decreased as the viewing angle is increased. a first camera and a second camera adapted to image an imaged target, wherein the first camera includes a first lens adapted to converge light from the imaged target and a first sensor adapted to receive light transmitted through the first lens, wherein the second camera includes a second lens adapted to converge light from the imaged target and a second sensor adapted to receive light transmitted through the second lens, wherein the first camera and the second camera are placed away from each other, wherein a center of the first sensor is shifted from an optical axis of the first lens by a first shift distance (d) away from the second camera in a first direction parallel to a straight line connecting a center of the first lens and a center of the second lens, and wherein a center of the second sensor is shifted from an optical axis of the second lens by a second shift distance (d) away from the first camera in the first direction, characterized in that, the first shift distance (d) is larger than D × f1 × L / { (L-f1)}, and the second shift distance (d) is larger than D × f2 × L / { (L-f2)}, where f1 is a focal length of the first lens, f2 is a focal length of the second lens, D is a distance between a center of the first lens and a center of the second lens, and L is a maximum distance allowing the acquisition of a signal that has a sufficient accuracy for the first and the second sensors (CSL, CSR) to calculate the distance to the imaged target, and wherein the first lens and the second lens both have a characteristic approximately same as that of an fθ lens at areas with small viewing angle θ, whereas the image height is smaller than that of an fΘ lens at areas with large viewing angle Θ, such that the increment of the image height is gradually decreased as the viewing angle is increased.