It has been reported that pain management by the PCA pump is useful. But many problems related with the use of computer-controlled mechanical PCA pump have been pointed out. Psychological stress both of patients and nurses were the main problems. From the analysis of these problems, explanation booklet of “before use” was introduced. How to handle the PCA pump itself, how to cope with alarm events, how to replace battery, and so on, were explained simply in this booklet. Explanation picture sheet was also introduced. Another unexpected problem was the obstruction of the line. We examined this obstruction phenomenon very carefully and concluded that the cause of obstruction was the air trap in the micro bacterial filter. After changing it to a filter with an air vent system, this obstruction alarm event disappeared. After the introduction of these easy-to-understand booklet, sheet, and micro bacterial filter with air vent system, dramatically big improvement was achieved.