This device is provided with: a main shaft (20) onto which a tool (100) is detachably mounted; a rod (30) slidably supported by the main shaft (20) and configured to attach or detach the tool (100) to or from the main shaft (20) through a sliding action; a fluid channel (32) formed in the rod (30); fluid feed device (51, 70) configured to feed a fluid into the fluid channel (32); a plurality of fluid channels for seating detection (24) for detecting when the main shaft (20) and the tool (100) are in a seated state, the fluid channels for seating detection (24) being formed in the main shaft (20) so as to communicate with the fluid channel (32) when the rod (30) is positioned at a first position; and a plurality of fluid channels for cleaning (25) for cleaning seating portions of the main shaft (20) and the tool (100), the fluid channel for cleaning (25) being formed in the main shaft (20) so as to communicate with the fluid channel (32) when the rod (30) is positioned at a second position different from the first position.