Errors in work in a bolt or nut tightening process are reduced to an extremely low level. Further, the process of the work is accurately recorded and quality of production processes is improved. A production management device receives information on a production instruction from a superordinate device, optically displays, according to the information, a socket to be selected for work to tighten a bolt or a nut, automatically recognizes a nut taken out from a socket holder, and alarms when the recognized socket and the displayed socket do not agree.