The purpose of this research is to develop the managerial disaster prevention diagnosis technique for small and medium-sized companies against large earthquakes. This paper examines whether the introduction of a " Fixed Assets to Fixed Liability Ratio (FA)" and a "Quick Assets Ratio (QA)" is possible as the managerial indexes which explain the concept chart of the "Business continuity plan (BCP)" of the companies. To obtain the basic information, 93 manufacturing companies in Aichi prefecture are investigated. The main results are summarized as follows;
1. FA is less than 100% and QA is 100% or more in 75% cases.
2. About 20% cases are insufficient in FA and QA.
3. The relation between FA and QA can be shown by a logarithmic formula.
4. Disaster prevention investment remaining power was shown concretely in value.
