PURPOSE: To properly arrange components in a block surface in designing operation by specifying the arrangement positions of the components on the block surface in a five-plane or three-plane drawing and displaying selected components as actual body figures on the same scale with the block.

CONSTITUTION: Plural hydraulic components obtained from a hydraulic circuit diagram are displayed in a component display frame 7 provided at part of a CRT screen 6, and an optional component is selected in the component display frame 7 by operator's operation. Then the arrangement position of the component is specified in one of block surfaces in the five-plane or three-plane drawing, and the selected component is displayed and arranged as the actual body figure on the same scale with the block. In the component display frame 7, a component figure which is obtained by simplifying the actual component figure and can be discriminated is displayed as an icon component. Further, the position of the component in any plane in the five-plane or three- plane drawing is specified by specifying two-dimensional coordinate size in an arrangement drawing in addition to cursor clicking operation. Further, the correspondence to a component which is already arranged is specified to array new components in a line.