At present, many production scheduling systems have been developed. However, a lot of customization according to individual production environment is required, and then a large investment for development and maintenance is indispensable. Therefore now the direction to construct scheduling systems should be changed. The final objective of this research aims at developing a system which is built by it extracting the scheduling technique automatically through the daily production scheduling work, so that an investment will be decreased. This paper shows a prototype of Gantt Chart Interface System that emulates the production scheduling work on papers. Through the analysis of operator's operations, this paper proposes how to extract the master information required by production scheduling. Using the information, the scheduling operators can be supported to accelerate the scheduling work easily and accurately without any restriction of scheduling operations. By installing this extraction mechanism, it is easy to introduce scheduling system without a lot of expense for customization. In this paper, the extraction mechanism of the master information and operator support functions are proposed through a model expressing a scheduling problem.