Machining jig for rotatably supporting workpiece with respect to tool of machine tool and machining system

A machining jig which rotatably supports a workpiece with respect to a tool of a machine tool, comprising:

• a seating part on which the workpiece is placed,
• a rotary drive part which rotates said seating part about a predetermined rotation axis,
• a clamp arm which has a rotary type clamp member which cooperates with said seating part to fasten a workpiece at a position separated from said seating part in a direction along the rotation axis of said seating part,
• a linear drive part which moves said clamp arm in a direction along a rotation axis of said seating part,
• a position adjusting part which adjusts a position of said clamp arm in a plane intersecting the rotation axis of said seating part, and
• a tilt adjusting part which adjusts a tilt of said clamp member so that a rotation axis of said clamp member becomes parallel with the rotation axis of said seating part.