A material holding apparatus adapted to be incorporated into a machine tool and to securely hold a worpiece, the material holding apparatus having an axial frontward region and an axial rearward region and comprising: a tubular chuck (14A, 14B) accomodated in the axial frontward region and having a holding section capable of opening and closing; an actuating member for actuating said holding section to open or close; and a driving mechanism for making said actuating member move between a closing-operation position allowing said holding section to securely hold a workpiece under a pressing force and an opening-operation position relieving said pressing force and allowing said holding section to release the workpiece; wherein said driving mechanism comprises a bidirectional driving member for selectively applying, to said actuating member, one of a normal driving force for making said actuating member move from said opening-operation position to said closing-operation position and a reverse driving force for making said actuating member move from said closing-operation position to said opening-operation position wherein said driving mechanism is capable of locating said actuating member at an intermediate position between said closing-operation position and said opening-operation position, characterized in that when said actuating member is located at said intermediate position, said holding section of said chuck (14A, 14B) holds the workpiece under a second pressing force smaller than said pressing force allowing said holding section to securely hold the workpiece, wherein the material holding apparatus further comprises a biasing member elastically biasing said actuating member axially rearward, and wherein, when said actuating member is located at said intermediate position, said second pressing force is generated by an elastic biasing force of said biasing member. a tubular chuck (14A, 14B) accomodated in the axial frontward region and having a holding section capable of opening and closing; an actuating member for actuating said holding section to open or close; and a driving mechanism for making said actuating member move between a closing-operation position allowing said holding section to securely hold a workpiece under a pressing force and an opening-operation position relieving said pressing force and allowing said holding section to release the workpiece; wherein said driving mechanism comprises a bidirectional driving member for selectively applying, to said actuating member, one of a normal driving force for making said actuating member move from said opening-operation position to said closing-operation position and a reverse driving force for making said actuating member move from said closing-operation position to said opening-operation position wherein said driving mechanism is capable of locating said actuating member at an intermediate position between said closing-operation position and said opening-operation position, characterized in that when said actuating member is located at said intermediate position, said holding section of said chuck (14A, 14B) holds the workpiece under a second pressing force smaller than said pressing force allowing said holding section to securely hold the workpiece, wherein the material holding apparatus further comprises a biasing member elastically biasing said actuating member axially rearward, and wherein, when said actuating member is located at said intermediate position, said second pressing force is generated by an elastic biasing force of said biasing member.