To simplify the generation of a document such as a daily report and a monthly report in a control system constituted by connecting PLCA1, B1 and C1 to which various units 12 being the objects of control and sensors 13 are connected to a host computer 11.

A writing part 26c in an application part 26 starts a spread sheet software installed in a spread sheet part 26a in response to distribution data from PLCA1, B1 and C1 such as working quantity. Data are sequentially written into the designated cell of the designated book of a work sheet in spread sheet software by a previously selected writing pattern. When writing is completed, it is preserved in the file of a designated book preserving destination in the table storage part 26b. The daily report is automatically generated by a template which is previously prepared with the collection of data and it is printed/outputted from a printing means 28. Thus, the daily report and the monthly report can automatically be generated.