An image capturing apparatus comprising an image capturing system and an image processing apparatus, wherein the image capturing system comprises a first image capturing system configured to capture a first image with a first parameter value as a value of an optical parameter, and a second image capturing system configured to capture a second image with a second parameter value as a value of the optical parameter, which is different from the first parameter value, and wherein the image processing apparatus is configured to process the first image and the second image so as to detect a corresponding pixel in the second image which corresponds to a target pixel in the first image, wherein the image processing apparatus comprises: an area setter configured to set a two-dimensional search area as a partial area in which the corresponding pixel is to be searched in the second image; and a detector configured to detect the corresponding pixel by searching the two-dimensional search area, wherein the optical parameter includes a focal length of an optical system in the respective image capturing system, characterized in that the area setter sets the two-dimensional search area, based on a predetermined range in which each of the first and second parameter values can change due to tolerances of the first and second image capturing systems, to be as narrow as possible so as to contain all epipolar lines that change in the second image as the first parameter value and the second parameter value change in the predetermined range. wherein the image capturing system comprises a first image capturing system configured to capture a first image with a first parameter value as a value of an optical parameter, and a second image capturing system configured to capture a second image with a second parameter value as a value of the optical parameter, which is different from the first parameter value, and wherein the image processing apparatus is configured to process the first image and the second image so as to detect a corresponding pixel in the second image which corresponds to a target pixel in the first image, wherein the image processing apparatus comprises: an area setter configured to set a two-dimensional search area as a partial area in which the corresponding pixel is to be searched in the second image; and a detector configured to detect the corresponding pixel by searching the two-dimensional search area, wherein the optical parameter includes a focal length of an optical system in the respective image capturing system, characterized in that the area setter sets the two-dimensional search area, based on a predetermined range in which each of the first and second parameter values can change due to tolerances of the first and second image capturing systems, to be as narrow as possible so as to contain all epipolar lines that change in the second image as the first parameter value and the second parameter value change in the predetermined range. an area setter configured to set a two-dimensional search area as a partial area in which the corresponding pixel is to be searched in the second image; and a detector configured to detect the corresponding pixel by searching the two-dimensional search area, wherein the optical parameter includes a focal length of an optical system in the respective image capturing system, characterized in that the area setter sets the two-dimensional search area, based on a predetermined range in which each of the first and second parameter values can change due to tolerances of the first and second image capturing systems, to be as narrow as possible so as to contain all epipolar lines that change in the second image as the first parameter value and the second parameter value change in the predetermined range.