According to the present invention, a display system of a turning work vehicle is used for the turning work vehicle in which a work machine having a bucket 8 can be offset relative to a revolving superstructure in the horizontal direction. The display system includes: an arithmetic unit that calculates the position of the bucket on the basis of a detection result obtained by a position detecting device provided on the turning work vehicle, and calculates a necessary revolving amount of the revolving superstructure and a necessary offset amount of the work machine that are needed to align a side section of the bucket with a side edge of a predetermined excavation area; and a display device that displays the positional relationship between the bucket and the predetermined excavation area.