Abstract: A floor-map display image that displays a floor-map image for an instrumentation panel room and the like in a nuclear plant, a hardware apparatus display image, and a maintenance tool display image are displayed in an multi-window manner on a display apparatus so that a hardware apparatus to be maintained and a maintenance tool are collated with each other in a floor map.

Abstract: Visual noise removal processing means applies processing to suppress an influence of a fluctuation of a parameter given to an arrow to be displayed on a display device according to at least one of a changing trend of the parameter, a difference between the current value and the last value of the parameter, and the current value of the parameter. Consecutive appearances counting means counts the number of times a same changing trend appears consecutively in the parameter. Arrow highlight degree setting means increases a degree of highlight of the arrow as the number of times becomes larger.