In order to easily and inexpensively renovate grasslands whose yield had declined or botanical composition had deteriorated, a new pasture renovator based on the design of a rotary tilling device that performs narrow ditching, over-sowing in the ditch, fertilizer application, covering with soil and compacting in one pass was developed. It makes a T-shaped ditch with a combination of shallow L-shaped working blades and deep-tilling plate-shaped straight blades. It is mounted on a tractor with a power exceeding 44 kW. Test results revealed that this machine enabled to save more labor in partial tilling renovation than in overall renovation and that it effectively improved the vegetation of the land.