The present invention provides a wiper device of working machinery capable of wiping both of a left upper part and a right upper part of a front window of a cabin of the working machinery. The wiper device of the working machinery is constituted capable of controlling a first electric motor 22 included in a first electric motor device 21 and a second electric motor 26 included in a second electricmotor device 25 so that first and second wiper bodies 20, 24 do not interfere with each other by providing the first wiper body 20 and the first electric motor device 21 to drive this wiper body on aleft side part of the front window 5 in front of the cabin 4 and providing the second wiper body 24 and the second electric motor device 25 to drive this second wiper body on a right side part of thefront window 5.