PURPOSE: To perform a color changing judgment so easy by finding a valve serving as a color changing judging condition of a pipeline system diagram, and installing a facility table, making a line between valves a table, and a line information table.

CONSTITUTION: The presence of a fluid in a pipeline is discriminated by opening or closing of a valve of a pipeline system diagram being controlled by a computer 10 and displayed on a display part 4. There are provided with a facility table A, showing the whole lot of a unit line where a flow is varied by valve opening or closing at each valve and a line information table B having a counter at each unit line. With this constitution, preparation of the tables is easy and, what is more, a color change can be done quickly.