Clamping device

A clamping device that is able to fix a fixation-target object to a base body and to position the fixation-target object with respect to the base body, the clamping device comprising:

• a fluid pressure cylinder fixed to the base body;
• and
• an annular member attachable to the fixation-target object, wherein
• the fluid pressure cylinder includes
• a cylinder main body,
• a first piston and a second piston each reciprocally movable with respect to the cylinder main body,
• a first cylinder chamber that drives each of the first piston and the second piston to a fixation side,
• a second cylinder chamber that drives each of the first piston and the second piston to a fixation-release side, and
• an engagement portion that is able to be located on an inner peripheral side of the annular member and that is able to switch between a first state and a second state in response to a reciprocal movement of each of the first piston and the second piston, the first state being a state in which the annular member is not pressed, the second state being a state in which the annular member is pressed to the base body side, and
• the first piston, the first cylinder chamber, the second cylinder chamber, and the second piston are provided to be arranged side by side along a first direction from the base body side toward the fixation-target object side in an order of the first piston, the first cylinder chamber, the second cylinder chamber, and the second piston.