A dental prosthesis processing device that processes a workpiece made of ceramic or the like into a prosthesis of a desired shape includes one or more processing tools for processing a workpiece into a prosthesis of a predetermined shape; a spindle on which the processing tools are replaceably mounted and that is spatially movable in position; a processing tool replacement obstruction part located in close proximity to the processing tools and/or the spindle and configured to obstruct the processing tools from being replaced; and a controller configured to determine whether to replace the processing tools. Depending on whether the replacement is necessary or not, the controller allows or prevents the processing tools from being replaced by bringing the processing tools and/or the spindle and the processing tool replacement obstruction part away from or close to each other.