Measurement of airborne radiation must be performed before and after decontamination work to confirm whether decontamination has actually been performed. Conventional measurement procedures require enormous amounts of work. Without using a specific mark, it is difficult to find the same measurement location before and after the decontamination work. To overcome these problems, we developed an airborne radiation mapping system that can perform measurements precisely and quickly. The system enables the simultaneous measurement of airborne radiation at multiple heights by utilizing multiple measurement units. In addition, we developed a new navigation system to reduce workload. The airborne radiation mapping system facilitated quick measurement and easy movement.