PURPOSE: To make compact structure available for a machine by providing an upper frame equipped with front wheels and a lower frame equipped with rear wheels and by connecting the lower frame to the upper frame at point in the middle of the upper frame so that the frames become capable of making relative rocking motion around the vertical axis.

CONSTITUTION: An upper frame 2 equipped with front wheels and a lower frame 4 equipped with rear wheels are connected so that both the upper and the lower frames become capable of making relative rocking motion around the vertical axis Y. On the front part of the front frame 2, an hydraulic loader 5 is installed and, at the same time, an operating device 6 and an engine 7 are installed respectively over the axis Y and to the rear part thereof. Then the frame 4 is made a fuel oil tank 8, and a hydraulic cylinder 9 is installed extending over the frames 2 and 4, and by operation thereof, the frames can make rightward and leftward rocking movement around the axis Y. Furthermore a travel motor 16 is driven through a hydraulic pump 18, making the wheels travel. Thereby compact design can be feasible for lengthwise structure of a machine with a spacious operator's seat secured, utilizing a space over a bent part of the machine.