PURPOSE: To unequivocally calculate a derived solution, to increase the calculation speed, and to improve the precision of the derived error at the time of deriving the geometrical error of a robot including a direct-acting shaft, an NC working machine, or the like.

CONSTITUTION: The D-H notation is used to make a mechanism, whose front end a working tool is attached to, into a model, and the position and the attitude of this working tool for operation of this mechanism are measured, and the model is used to estimate them, and these measured value (r) and estimated value r' are compared with each other to derive the error of the mechanism. In this case, only parameters to change the coordinates of a driving shaft of the mechanism are used in the model; and when the model is used to estimate the position and the attitude of the working tool, coordinate transform S operation based on the rotation parameter which directs the driving shaft, coordinate transform T operation based on the translation parameter which translates the driving shaft, and inverse transform S-1 operation of coordinate transform based on the rotation parameter are successively executed.