Disclosed is a display system for a working machine, adapted to display basic information at all times and to display, in case of an abnormality, details of a warning in addition to the basic information efficiently and in such a form as to enable an operator to reliably recognize details of the warning. A first warning display function 53b of a display controller 53, upon receiving an abnormality information signal relating to a charge warning, displays an appropriate warning icon 34a in a warning icon display region 42. A simplified basic-information display function 53e then displays simplified basic-information images 35 and 36, instead of basic-information images 31 and 32. This display consequently generates a free (unoccupied) area 44 within the basic information display region 41, the area 44 within the basic information display region 41 corresponding to an area other than an area in which the simplified basic-information images are displayed. A second warning display function 53f displays, in the free area 44, a second warning message 37 inclusive of a "Charge warning" message as display details of the warning icon 34a, and of character information relating to a simplified remedial action. The operator can reliably recognize the "Charge warning" and understand its details as well, by viewing the second warning message 37 in addition to the warning icon 34a.