To reduce the required number of frame, and reduce the number of part items by providing a fuel tank on a main frame, which forms a part of an under carriage and which forms the fore and aft direction of the under carriage, and a frame dedicated so as to support the fuel tank.

At the time of providing a fuel tank 3 in a combine, the fuel tank 3 is placed on a main frame 4, which forms a part of an under carriage 2 and which is formed in the fore and aft direction, and a frame 5, which is dedicated so as to support the fuel tank 3. This frame 5 is fixed to a lateral frame 2b of a rear part and a lateral frame 5a in front of the lateral frame 2b by welding. With this structure, the main frame 4 is an important part for forming the under carriage 2, and since the strength thereof is set at a high degree, the fuel tank 3 is stably supported. Furthermore, since the fuel tank 3 is provided in rear of the under carriage 2, namely, in rear of the combine, maintenance work is facilitated by removing the fuel tank 3.