1. A calibration device for a range image sensor which is attached at a mobile body, the calibration device being configured so as to calibrate an attachment error to the mobile body of the range image sensor, which is attached at a mobile detects a distance of each direction within a detection range and generates a range image data from the detected distance information, in a state where the range image sensor is attached at the mobile body, the calibration device comprising: a data receiving portion for receiving a calibration-subject data, which is the range image data including a calibration target, from the range image sensor, the calibration target being set within the detection range and is configured so as to include a first plane surface and a second plane surface, which differs from the first plane surface; a plane surface specifying portion for specifying each of the first plane surface and the second plane surface in a three-dimensional reference coordinate system on the basis of the calibration-subject data; a normal vector calculating portion for calculating a normal vector of each of the specified first and second plane surfaces in the three-dimensional reference coordinate system; and a rotation calculating portion for calculating a rotation of the range image sensor caused by the attachment error to the mobile body in the three-dimensional reference coordinate system on the basis of a posture information of the calibrated target, which has already been recognized, and the normal vector in the three-dimensional coordinate system.