To provide general usability to a jig functioning as a lower die.

A forming device is provided with a jig functioning as a lower die in combination with a movable stylus 8 in the three dimensional direction and a pin assembly made of an assembly of many pins displaceable in the up/down direction. Each pin is capable of holding an arbitrary height position by itself. Before forming of an actual formed part, based on a continuous forming NC data, the respective pin height positions of the pins 4 are adjusted, the formed face 14a of an arbitrary three dimensional shape corresponding to the envelope of the tip faces of each pin 4 is generated on the tip face of the pin assembly 14.