A camera calibration method which calculates camera parameters of at least three cameras by use of a calibration point, comprising: acquiring calibration point data which is stored in a first memory and which includes a three-dimensional coordinate set of the calibration point and an image coordinate pair corresponding to the calibration point in a camera image of each of the cameras; acquiring camera parameters of each camera, which are stored in a second memory, wherein the camera parameters include parameters concerning the positioning of the cameras; calculating a view angle-corresponding length for each pair of the cameras based on the calibration point data and the camera parameters, wherein each view angle-corresponding length for each pair of the cameras correlates to a size of an angle of view of the pair of the cameras viewing the calibration point, the angle of view of the pair of the cameras being formed by the two lines of sight from the pair of the cameras to the calibration point; calculating a three-dimensional position of a measurement point for each pair of the cameras by use of parallax of the calibration point between the cameras in the pair of the cameras based on the image coordinate pairs corresponding to the calibration point and the camera parameters, wherein each three-dimensional position of a measurement point corresponds to a three-dimensional position of the calibration point; weighting the three-dimensional position of each measurement point by use of the view angle-corresponding length of each pair of the cameras corresponding to each measurement point; calculating a three-dimensional position of a unified point formed by unifying the weighted three-dimensional positions of each measurement point; updating the camera parameters based on the three-dimensional coordinate set of the calibration point and the three-dimensional position of the unified point; and outputting the updated camera parameters, at least one of the process to the process being executed by a processor. acquiring calibration point data which is stored in a first memory and which includes a three-dimensional coordinate set of the calibration point and an image coordinate pair corresponding to the calibration point in a camera image of each of the cameras; acquiring camera parameters of each camera, which are stored in a second memory, wherein the camera parameters include parameters concerning the positioning of the cameras; calculating a view angle-corresponding length for each pair of the cameras based on the calibration point data and the camera parameters, wherein each view angle-corresponding length for each pair of the cameras correlates to a size of an angle of view of the pair of the cameras viewing the calibration point, the angle of view of the pair of the cameras being formed by the two lines of sight from the pair of the cameras to the calibration point; calculating a three-dimensional position of a measurement point for each pair of the cameras by use of parallax of the calibration point between the cameras in the pair of the cameras based on the image coordinate pairs corresponding to the calibration point and the camera parameters, wherein each three-dimensional position of a measurement point corresponds to a three-dimensional position of the calibration point; weighting the three-dimensional position of each measurement point by use of the view angle-corresponding length of each pair of the cameras corresponding to each measurement point; calculating a three-dimensional position of a unified point formed by unifying the weighted three-dimensional positions of each measurement point; updating the camera parameters based on the three-dimensional coordinate set of the calibration point and the three-dimensional position of the unified point; and outputting the updated camera parameters, at least one of the process to the process being executed by a processor.