To rationally constitute a display device capable of displaying attribute information of a duct constitution institution at an easily grasped form.

The duct display device is provided with a duct display part D which displays layout of a duct on a display 2 based on duct information and an attribute information display part E which displays the attribute information about the institution constituting the duct on the display 2 and constituted so that the attribute information display part E displays the attribute information in any of a first display mode which displays the attribute information like a row at an initial display position and a second display mode which displays a plurality of attribute information at optionally set positions.