The DQMS (Defence Quality Management System) is a certification system that manages participating companies to improve the quality of munitions. Since Korean Defense Specification (KDS) for DQMS certification that was established by adding military requirements based on the ISO quality standard, many companies complain that they should pay too much effort into the preparation process. However, it is hard to find helpful information on the preparation process because we have been only interested in the effect of DQMS acquisition. The purpose of this paper is to provide helpful information to companies preparing for DQMS certification. We surveyed the degree of difficulty and importance of the DQMS requirements from the companies with certification experience, and performed IDA (Importance-Difficulty analysis) by dividing the companies into the main contractor and the subcontractor. The result of IDA shows that there is a different recognition to the DQMS certification between main-contracting and sub-contracting companies. Subcontractor has more difficulties than main contractor in preparing the DQMS certification. In addition, we are able to identify the difficult and important requirements in the preparation process to the DQMS certification. Both main contractor and subcontractor have difficulty to the requirements related to configuration or validation such as ‘customer controls configuration’, ‘configuration review shall be implemented’ and ‘design and development validation documentation.’ The requirements related to customers are important to main contractor but the subcontractor regards difficult requirements as important ones. The result of this paper would be helpful to both the company preparing for DQMS and the munitions quality assurance agency.