This study analyzed fall accidents involving boatswain’s chairs over the past ten years to investigate their underlying causes and effective preventive measures. The fall accidents in this study were classified according to construction type, work category, and sequence of work. Next, their direct causes were identified by applying the concept of serious injury factor. A focus group interview was conducted with six experts in boatswain’s chair-type scaffolding to derive preventive measures. The results of the investigation indicate that the majority of accidents occurred in maintenance works among construction types, and painting, caulking, and cleaning tasks among work categories. In terms of work sequence, most fall accents occurred while working with descending due to rope defects (loosening, breakage, or insufficient length) and anchorage failures. Based on these findings, two key preventive measures were proposed: (1) installing lifelines as a fail-safe measure to provide safety redundancy, and (2) implementing inherent safety measures to prevent rope defects and failures such as regular inspections, use of high-performance ropes, and ensuring proper anchorage strength. The findings of this study can be utilized in development of effective safety guidelines and policies for boatswain’s chair operations.