Identifier management method and reading device

The identifier output method is an identifier output method executed by a welding system, and comprises the following steps: acquiring information of identifiers of a plurality of source workpieces to which identification symbols are assigned; an identifier set for a workpiece to be welded produced by a welding process using the plurality of source workpieces is selected from the identifiers of the plurality of source workpieces according to a given rule, and after the selection, any one of the identification symbols given to the plurality of source workpieces is read by a reading device. And outputting the information of the selected identifier as the identifier of the welded workpiece to a reading device. 标识符输出方法为通过焊接系统执行的标识符输出方法，取得被赋予了识别符号的多个源工件各自的标识符的信息，从多个源工件各自的标识符之中根据给定的规则选择对通过使用了多个源工件的焊接工序生产的被焊接工件设定的标识符，在选择后，在通过读取装置读出了对多个源工件分别赋予的识别符号之中的任意的识别符号的情况下，将所选择的标识符的信息作为被焊接工件的标识符输出到读取装置。