An area division unit divides a part placement area into a plurality of divided areas based on an area granularity. A part gravity value operation unit and a parts replacement unit extract a set of parts at each end of a connection line for each placement according to a connection line definition table and a parts placement table. If each part belonging to the set of parts obtained in the second process exists in a different divided area for each connection line, then the placement of each part belonging to a divided area is amended in the divided area in such a way that a connection line length between the parts can be shortened. A repetition control unit repeats a series of the above described processes while optionally changing a division starting position of the area division unit. An area granularity change unit repeats the series of the processes up to this point while gradually reducing an area granularity each time the above described series of processes terminate. A termination judgment unit determines the termination of a process, and outputs the position of a part as an output result from the parts placement table.