Provided is a chuck structure, which is configured to chuck an annular workpiece from a radially outer side of the workpiece. The chuck structure includes: leaf spring members arranged at a predetermined pitch along a circumferential direction of the chuck structure so as to be symmetrical with respect to a mechanism center axis; chuck claw members mounted to distal ends of the leaf spring members, respectively; and a pressing force applying mechanism configured to apply a force of pressing the leaf spring members radially inward, to thereby elastically press the chuck claw members onto a radially outer surface of the workpiece.