A stereo camera device comprising: a first imaging element and a second imaging element; a first circuit element and a second circuit element disposed between the first imaging element and the second imaging element, wherein the first circuit element has a larger heat generation amount than the second circuit element; and a casing (1a; 1b; 1c; 1d; 1e; 1f; 1g) for retaining the first imaging element, the first circuit element, the second circuit element, and the second imaging element in order, wherein a plane, which is passing through a midpoint between the first imaging element and the second imaging element and which has a normal line connecting the first imaging element and the second imaging element, is defined as a stereo camera device center, a plane, which is passing through a centroid of the first imaging element and which has a normal line connecting the first imaging element and the second imaging element, is defined as a first imaging element center, a plane, which is passing through a centroid of the second imaging element and which has a normal line connecting the first imaging element and the second imaging element, is defined as a second imaging element center, a plane, which is passing through a centroid of the first circuit element and which has a normal line connecting the first imaging element and the second imaging element, is defined as a first circuit element center, a plane, which is passing through a centroid of the second circuit element and which has a normal line connecting the first imaging element and the second imaging element, is defined as a second circuit element center, a second distance (Lm) from the second circuit element center to the stereo camera device center is longer than a first distance (Lf) from the first circuit element center to the stereo camera device center in a direction connecting the first imaging element and the second imaging element, a third distance (Lcr) from the first circuit element center to the first imaging element center is longer than the first distance (Lf), and a fourth distance (Lcl) from the second circuit element center to the second imaging element center is longer than the second distance (Lm). a first imaging element and a second imaging element; a first circuit element and a second circuit element disposed between the first imaging element and the second imaging element, wherein the first circuit element has a larger heat generation amount than the second circuit element; and a casing (1a; 1b; 1c; 1d; 1e; 1f; 1g) for retaining the first imaging element, the first circuit element, the second circuit element, and the second imaging element in order, wherein a plane, which is passing through a midpoint between the first imaging element and the second imaging element and which has a normal line connecting the first imaging element and the second imaging element, is defined as a stereo camera device center, a plane, which is passing through a centroid of the first imaging element and which has a normal line connecting the first imaging element and the second imaging element, is defined as a first imaging element center, a plane, which is passing through a centroid of the second imaging element and which has a normal line connecting the first imaging element and the second imaging element, is defined as a second imaging element center, a plane, which is passing through a centroid of the first circuit element and which has a normal line connecting the first imaging element and the second imaging element, is defined as a first circuit element center, a plane, which is passing through a centroid of the second circuit element and which has a normal line connecting the first imaging element and the second imaging element, is defined as a second circuit element center, a second distance (Lm) from the second circuit element center to the stereo camera device center is longer than a first distance (Lf) from the first circuit element center to the stereo camera device center in a direction connecting the first imaging element and the second imaging element, a third distance (Lcr) from the first circuit element center to the first imaging element center is longer than the first distance (Lf), and a fourth distance (Lcl) from the second circuit element center to the second imaging element center is longer than the second distance (Lm).