Rotating table device

A rotating table device comprising:

• a base member;
• a rotating member supported by the base member so as to be rotatable about a predetermined axis;
• a brake disk that is secured to the rotating member;
• and
• a clamping mechanism that clamps the brake disk and maintains the rotating member in a stationary state with respect to the base member;
• wherein the clamping mechanism is provided with a piston that is attached so as to be movable, in a direction along the predetermined axis with respect to the base member, between a clamped position at which the clamping mechanism presses the brake disk in a plate-thickness direction via a working fluid and an unclamped position at which the clamping mechanism is separated from the brake disk;
• a plate spring that is secured to the piston and the base member and that is formed to bias the piston toward the clamped position via only a restoring force generated by elastic deformation of the plate spring when a pressure of the working fluid is not acting;
• and
• a coil spring that is disposed between the piston and the base member and that is configured to interpose the piston between the plate spring and the coil spring, and that constantly biases the piston toward the clamped position via a restoring force generated by elastic deformation of the coil spring.