PURPOSE: To automatically obtain intended figures next and thereafter by learning a geometric condition alteration command that an operator indicates to a figure which is temporarily deformed.

CONSTITUTION: Geometric conditions 23 of respective elements 1-8 constituting a figure 10 and the altering process priority 24 when the respective elements are altered are stored in a geometric condition data storage part 13 and in response to the input of a size alteration command, the respective elements are altered in order so that the size of a specific part of the figure reaches a specified size while it is judged whether the geometric conditions are met according to the altering process priority of the corresponding elements stored in the geometric condition data storage part 13. According to the geometric condition alteration command, whether the geometric conditions of the specified element are effective or ineffective is changed and the figure is altered again, and the altering process priority stored in the geometric condition data storage part is altered lastly according the the changed effectiveness or ineffectiveness of the geometric conditions.