A production information collecting system that includes a plurality of processing machines (10A, 10B), a plurality of control units (11A, 11B) that are configured to absorb data from the processing machines (10A, 10B), and are further configured to output logging data based on the absorbed data, and a plurality of data output apparatuses (12A-1, 12A-2, 12B-1) that are configured to output data not included in the logging data, the plurality of data output apparatuses (12A-1, 12A-2, 12B-1) being measurement devices installed in the processing machines (10A, 10B) or switch on/off detectors installed in the processing machines (10A, 10B), the production information collecting system being configured to collect the data from each of the plurality of processing machines (10A, 10B) via each of the "plurality of control units (11A, 11B) and via each of the plurality of data output apparatuses (12A-1, 12A-2, 12B-1), the production information collecting system comprising a plurality of slave units (2A-0, 2A-1, 2A-2, 2B-0), each of the plurality of slave units (2A-0, 2A-1, 2A-2, 2B-0) is configured to function as a slave station, and a computer system that is configured to function as a master station with respect to the slave stations, characterized in that: the plurality of slave units (2A-0, 2A-1, 2A-2, 2B-0) and the computer system are connected in series; each of the plurality of slave units (2A-0, 2A-1, 2A-2, 2B-0) is connected to each of the plurality of control units (11A, 11B) and the plurality of data output apparatuses (12A-1, 12A-2, 12B-1), and is configured to, in response to a request from the computer system, attach address data to the logging data from each of the plurality of control units (11A, 11B), or attach the address data to the data not included in the logging data from each of the plurality of data output apparatuses (12A-1, 12A-2, 12B-1), and is further configured to transmit the logging data to which the address data is attached or the data not included in the logging data to which the address data is attached to the computer system such that the computer system receives the logging data to which the address data is attached or the data not included in the logging data to which the address data is attached; and the computer system is configured to receive the logging data to which the address data is attached or the data not included in the logging data to which the address data is attached from each of the plurality of the slave units (2A-0, 2A-1, 2A-2, 2B-0), the computer system is further configured to delete predetermined data from the logging data, and the computer system is further configured to store the logging data from which the data has been deleted and the data not included in the logging data. the plurality of slave units (2A-0, 2A-1, 2A-2, 2B-0) and the computer system are connected in series; each of the plurality of slave units (2A-0, 2A-1, 2A-2, 2B-0) is connected to each of the plurality of control units (11A, 11B) and the plurality of data output apparatuses (12A-1, 12A-2, 12B-1), and is configured to, in response to a request from the computer system, attach address data to the logging data from each of the plurality of control units (11A, 11B), or attach the address data to the data not included in the logging data from each of the plurality of data output apparatuses (12A-1, 12A-2, 12B-1), and is further configured to transmit the logging data to which the address data is attached or the data not included in the logging data to which the address data is attached to the computer system such that the computer system receives the logging data to which the address data is attached or the data not included in the logging data to which the address data is attached; and the computer system is configured to receive the logging data to which the address data is attached or the data not included in the logging data to which the address data is attached from each of the plurality of the slave units (2A-0, 2A-1, 2A-2, 2B-0), the computer system is further configured to delete predetermined data from the logging data, and the computer system is further configured to store the logging data from which the data has been deleted and the data not included in the logging data.