With the purpose of developing effective teaching materials for business Japanese, this study makes a comparison and examination of the use of 'clarification questions' by native Japanese businessmen and business Japanese learners. The result of this analysis shows that there are only very limited forms of 'clarification questions' which the learners are able to use, and only for limited functions. In the future, teaching materials should be developed to state clearly the function of 'clarification questions' to the learner, and to include tasks which make the learners aware of these functions as an integral part of their studies.