The BOM(Bill Of Material) contains various important information for establishing production scheduling and purchasing process. For effective and efficient constructing of the BOM, some methods, such as, conventional BOM, Modular BOM and Generic BOM are developed. Many companies input the BOM information with manual process. During this process, no one can avoid human errors, that is input error and to omit input necessary Information. We must to remove the possibility of these human errors, and to construct BOM effectively. To do this, we try to take the BOM from CAD data automatically We have developed a supporting system for extracting BOM from AutoCAD files.