To increase an engine output during turn so as to be able to make turn stably in a wet paddy field working machine, which makes its work inside on the wet paddy field, like a combine or a rice planting machine.

A wet paddy field running vehicle transmits the power of an electronic governor type engine E to left and right running devices and power transmission to left and right steering devices can be set to ON and OFF independently by means of the turning motion of a steering lever. In this case, such means are provided as a running state mode/working condition mode switching means 22, a steering lever left/right turning motion detecting means, a non-working state detecting means, an accelerator lever position detecting means 31, a fuel injection quantity changing means 11 and a fuel injection timing changing means 12, and when the steering lever is given its turning motion to make turning run in a wet paddy field in non-working state, the engine output is increased by a set quantity.