A vehicle-mounted stereo camera device that achieves high-precision distance detection is provided, including a left camera and a right camera disposed to cause visual fields to overlap each other, a first enclosure and a second enclosure that enclose the left camera and the right camera and have portions within the visual fields of the left camera and the right camera, respectively, and a stereo processor that calculates a distance to a body outside the vehicle based on images captured by the left camera and the right camera and on positions of the left camera and the right camera on the vehicle. The stereo processor detects displacement amounts of the left camera and the right camera based on amounts of change in positions of the first enclosure and the second enclosure within the visual fields of the left camera and the right camera, and changes a cutout position in the images captured by the left camera and the right camera.