Recently, a lot of social systems have been computerized using Information Technology (IT). It is no exception in hospitals. Hospital support systems are also rapidly being computerized using such as Diagnosis Reservation System, Ordering System for Drug Prescriptions, Electronic Medical Record (EMR) and so on. In the immediate future, all of medical data will be stored to the database server in the hospital, and it is considered that complete paper-less and film-less system in hospitals become reality. These stored data, however, is not used effectively for analysis because of the great deal of the data and its variety - image data, numerical data, text data and so on. Previously, knowledge discovery methods from numerical medical database were studied and discussed actively. Text mining method for medical data, however, has not been enough discussed. This study discusses knowledge discovery method from Electronic Medical Records using Self Organizing Map (SOM) and its possibility. As the first step of this research, this paper describes the outline of keyword mapping method using SOM from Incident Reports. This paper also discusses the keyword extraction method from EMR and the coding method of SOM.
