1. A measuring system having a light receiving device and a multi-jointed robot configured such that the light receiving device is capable of moving relative to a target to be measured, the measuring system comprising: a measurement position/orientation determining means for determining a plurality of sets of positions and orientations of the robot in which the target is captured in a field of vision of the light receiving device; a positioning means for sequentially positioning the robot at each position and orientation determined by the measurement position/orientation determining means; a target detecting means for detecting the geometrical feature of the image of the target imaged on a light receiving surface of the light receiving device; a robot moving means for moving the robot, from a start point or each position and orientation of the robot determined by the determining means, such that the geometrical feature of the image of the target on the light receiving surface of the light receiving device satisfies a predetermined condition; a terminal point storing means for storing the position and the orientation of the robot after the robot is moved by the robot moving means, as a terminal point associated with each start point; and a calculating means for calculating errors of mechanical parameters of the robot based on the position and the orientation of the robot at each terminal point stored in the terminal point storing means.