PROBLEM TO BE SOLVED: To improve trench digging work efficiency by continuously turning a traveling machine body and continuously performing trench digging work, and forming a trench with a favorable draining function by forming the dug trench continuously.SOLUTION: A fitting frame 3 is connected to a traveling machine body 1 by a connecting mechanism 2, and a machine frame 4 is connected to the fitting frame. The machine frame includes trenching bodies 6 and 7 capable of trenching a field surface M, and a plow member 10 capable of scooping field soil at a position rearward the advancing direction of the trenching bodies and discharging it laterally. The machine frame is connected horizontally turnably to the fitting frame with a pivot mechanism. The machine frame further includes a position fixing mechanism 32 capable of selectively allowing and inhibiting the horizontal turning of the machine frame.
