Main shaft device and machine tool provided with same

A main shaft device comprising:

• a main shaft, onto a seating face of which is detachably mounted a tool that performs predetermined machining on an object to be machined or a tool holder to which the tool is attached;
• a rod slidably supported by the main shaft and configured to attach or detach the tool or the tool holder to or from the main shaft through a sliding action;
• a fluid channel formed in the rod;
• fluid feed device configured to feed a fluid into the fluid channel;
• a plurality of fluid channels for seating detection for detecting when the main shaft and the tool or the tool holder are in a seated state, the fluid channels for seating detection being formed in the main shaft so as to communicate with the fluid channel when the rod is positioned at a first position as a result of the sliding action;
• and
• a plurality of fluid channels for cleaning for cleaning seating portions of the main shaft and the tool or the tool holder, the fluid channels for cleaning being formed in the main shaft so as to communicate with the fluid channel when the rod is positioned at a second position as a result of the sliding action, the second position being different from the first position, wherein
• the rod is movable to a third position as a result of the sliding action, the third position being different from the first position and the second position, and
• when the rod is positioned at the third position, the fluid channel communicates with neither the fluid channels for seating detection nor the fluid channels for cleaning.