As a typical high wear-resistant hard material, WC/Co system cemented carbides are now widely used in various press-stamping dies and cutting tools for industrial applications. In recent years in Japan, a rapid sintering method called Spark Plasma Sintering (SPS) method or Pressure assisted Pulsed Electric Current Sintering (PECS) method has attracted attention to fabrication of dense bulk Functionally Graded Materials (FGMs) and Nano-phase materials. In order to improve the mechanical properties of monolithic hard materials into the surface with high wear-resistance and the inside with high toughness with more functionality, a compositionally graded WC/Co/Ni system FGM was studied. Using an Automatic FGM Manufacturing SPS machine, Square-shaped Large-size WC/Co/Ni system FGMs of 70mm (width) X 100mm (length) X 8 similar to 60mm (thickness) with 3-layers graded composition of WC0.5 mu m/Co6 wt%, WC3.5 mu m/Col 5 wt% and WC5 mu in / Ni20 wt% were homogeneously fabricated in a cycle time of one per less than one hour. The hardness of the top and bottom layers containing 6 wt% Co, 20 wt% Ni were 20 GPa and 8 GPa respectively. The grain growth of the 0.5, 3.5 and 5 mu m WC starting powder particles were minimized and well controlled, WC/Co and WC/Ni FGM systems were also studied. The developed WC/Co/Ni FGM showed a new weldable function to normal steel materials without any cracks and delaminations. The FGMs were practically applied to a screw component of extruding machine as the practical industrial use. It was successfully achieved more than 3 times longer tool life time at economical running cost. The gradient functions in both of weldability and machinability contribute to the application field in Tool & Die industry.