To provide a turning-over implement having turning-over ability improved by a turning-over cylinder capable of relaying plowed soil with time lag, a plow structure having synthesized forces, and a timely variable plow angle, and capable of casting the soil rearward.

The turning-over operation system obtained by combining a grooved pair disk, a turning-over cylindrical device and a plow angle-changing device can relay the plowed soil with the time lag by a shallow layer soil-plow 13 and a deep layer soil plow 15, has the turning-over ability improved by the synthesis of the forces by a handle-rowing arm 25, a fulcrum shaft 27 and a ship-bottom arm 33, and can cast the soil rearward by a screw turning-over cylinder. As a result, the plowed soil can be restored by turning over vicious insects and bacteria thickly growing in the shallow layer soil, and fatigue-accumulated obstinate soil to contribute the stable production by a farmer.