An excavation support database 40 includes a display table 47 and a display specifics table 48, which serve as storage means dedicated for display. The state of a working region per mesh is stored in the display table 47, and a discriminative display method (display color) is stored in the display specifics table 48 corresponding to the state per mesh. Reference is made to the display specifics table 48 on the basis of the state (height) per mesh, which is stored in the display table 47, to read the corresponding display color from the display specifics table 48, thereby displaying the state of the working region in a color-coded manner. Operation support and management realized with this system can easily be employed in different types of working machines in common and can inexpensively be performed with ease.