This paper has proposed a mapping system to build the RSSI-based fingerprint database for indoor localization. The mapping system has been developed practically to achieve two main objectives, fast and accurate radio-map construction. For the first aim, we implement the specially designed handheld mapping cart consisting of an odometer, a LiDAR, and a WLAN receiver in order to rapidly measure the environmental data at each area. To accomplish the rest goal, we suggest the map building algorithms employing the scan-matching, the graph-based optimization, and probabilistic median filter by using the gathered environmental data. The experiment has been performed in real office space to demonstrate the practical usability of the proposed method. And finally, we remark the conclusion and offer the future works to improve the mapping system of RSSI-based fingerprint database.