The utility model provides a rigidity that operating vehicle, the board that need not increase the side guide rail is thick, just can improve the ladder type frame. Maize picker ( operating vehicle) has the ladder type frame, and this ladder type frame includes: front wheel axle installation portion, rear wheel axle installation portion, and supply the engine to carry the engine year portion of putting of putting between front wheel axle installation portion and rear wheel axle installation portion. The side guide rail of ladder type frame includes: the front side protruding portion, this front side protruding portion is outstanding towards the below apart from the nearer position of front wheel axle installation portion compared with rear wheel axle installation portion, and the rear side protruding portion, this rear side protruding portion is outstanding towards the below apart from the nearer position of rear wheel axle installation portion compared with front wheel axle installation portion. Incline in the front and parallelly set up the sub vehicle frame with the mode that can go on installing and removing with the side guide rail between protruding portion and the rear side protruding portion. The rigidity of ladder type frame rises and erects the degree of sub vehicle frame in other words.
