A substrate production line (1, 10) comprising: an external memory device multiple substrate production machines (11, 12, 13, 14, 15) arranged in a line from upstream to downstream and configured to each load a substrate from an upstream side, perform production work on the substrate in accordance with a type of the substrate, and unload the substrate to a downstream side; a shared folder on the external memory device, wherein each of the substrate production machines (11, 12, 13, 14, 15) is able to create electronic files in the shared folder and is able to recognize the contents of files inside the shared folder; a substrate type identifying section provided on the substrate production machine (11, 12, 13, 14, 15) furthest upstream in the line and configured to identify the type of the substrate before the substrate is loaded; a file creating section (81, 83) provided on the substrate production machine other than the substrate production machine (11, 12, 13, 14, 15) furthest downstream in the line and configured to create in the shared folder a substrate type information file (FL1, FL2, FL3) including substrate type information indicating the type of the substrate when unloading the substrate; and a file recognizing section (93, 95) provided on the substrate production machine (11, 12, 13, 14, 15) other than the substrate production machine (11, 12, 13, 14, 15) furthest upstream in the line and configured to recognize the contents of files inside the shared folder the substrate type information file (FL1, FL2, FL3) created by the substrate production machine (11, 12, 13, 14, 15) directly adjacent at the upstream side before the substrate is loaded, the substrate production line (1, 10) is characterized by: a file deleting section (94, 96) provided on the substrate production machine (11, 12, 13, 14, 15) other than the substrate production machine (11, 12, 13, 14, 15) furthest upstream in the line and configured to delete the board type information file recognized by the file recognizing section from the shared folder, wherein the shared folder is divided into multiple areas (31, 32, 33, 34) with corresponding restricted use, whereby each substrate production machine (11, 12, 13, 14, 15) other than the substrate production machine (11, 12, 13, 14, 15) furthest upstream in the line is configured to only create, recognize the contents of files inside the shared folder and delete board type information files in its own corresponding area (31, 32, 33, 34) of the shared folder. an external memory device multiple substrate production machines (11, 12, 13, 14, 15) arranged in a line from upstream to downstream and configured to each load a substrate from an upstream side, perform production work on the substrate in accordance with a type of the substrate, and unload the substrate to a downstream side; a shared folder on the external memory device, wherein each of the substrate production machines (11, 12, 13, 14, 15) is able to create electronic files in the shared folder and is able to recognize the contents of files inside the shared folder; a substrate type identifying section provided on the substrate production machine (11, 12, 13, 14, 15) furthest upstream in the line and configured to identify the type of the substrate before the substrate is loaded; a file creating section (81, 83) provided on the substrate production machine other than the substrate production machine (11, 12, 13, 14, 15) furthest downstream in the line and configured to create in the shared folder a substrate type information file (FL1, FL2, FL3) including substrate type information indicating the type of the substrate when unloading the substrate; and a file recognizing section (93, 95) provided on the substrate production machine (11, 12, 13, 14, 15) other than the substrate production machine (11, 12, 13, 14, 15) furthest upstream in the line and configured to recognize the contents of files inside the shared folder the substrate type information file (FL1, FL2, FL3) created by the substrate production machine (11, 12, 13, 14, 15) directly adjacent at the upstream side before the substrate is loaded, the substrate production line (1, 10) is characterized by: a file deleting section (94, 96) provided on the substrate production machine (11, 12, 13, 14, 15) other than the substrate production machine (11, 12, 13, 14, 15) furthest upstream in the line and configured to delete the board type information file recognized by the file recognizing section from the shared folder, wherein the shared folder is divided into multiple areas (31, 32, 33, 34) with corresponding restricted use, whereby each substrate production machine (11, 12, 13, 14, 15) other than the substrate production machine (11, 12, 13, 14, 15) furthest upstream in the line is configured to only create, recognize the contents of files inside the shared folder and delete board type information files in its own corresponding area (31, 32, 33, 34) of the shared folder.