This study focuses on staffs of convention bureaus and clarifies their know-how for attracting international conventions from a questionnaire survey. Convention bureaus play an important role to attract international conventions. A qualitative questionnaire survey highlighting issues raised in hosting international convention was conducted in February 2013 during Japan Congress and Convention Bureau (JCCB). Machine learning was conducted to clarify the experiences of those convention bureaus that had held more than one hundred international conventions in previous three years. The survey instrument was consisted of eight qualitative questions highlighting issues raised in hosting international convention. A total of twenty-seven questionnaires were collected from eight regions. The results show that the convention bureaus emphasize the importance of establishing formal meals, avoiding unreasonable demands, building large-scaled facilities, and offering environmentally-friendly alternatives.