PURPOSE: To manage measures without depending upon layer management and makes movement possible between the measures through easy operation by securing layers which have a new measure value as many as layers before measure value setting as the new measure value is set after a drawing is plotted with some measure value by using the layers.

CONSTITUTION: A measure 1 has layers 1-32, a measure 2 has the layers 1-32, and measures 3 and 4 are also the same. On a screen, a current layer (L) and a current measure (S), e.g. 'L=1, S=1' is displayed and when the measure is switched from 1 to 2 by measure switching, 'L=1, S=2' is displayed. The layer 1 of the measure 1 and the layer 1 of the measure 2 are different layers, but an operator need not pay attention to the switching of the layers. Therefore, the movement between the measures is made possible without preprocessing for layer use state investigation, and the user layers and measures are switched independently of each other to manage layers on a CAD data base.