A terrestrial laser scanner emerges as a main mapping technology for the indoor 3D model by providing fast and accurate 3D data. However, the field process to acquire the indoor 3D data using a terrestrial laser scanner heavily relies on the expert's field experiences. In this paper, the new method consisting of determination of optimal terrestrial laser scanner locations for indoor mapping using a genetic algorithm (GA) is proposed to acquire indoor 3D data more efficiently. The proposed method using GA utilizes building outlines extracted from 2D CAD drawings and it makes determination of the optimal locations and the number of scanner settings simple and fast. Furthermore, if the result of the proposed method is practically adopted with field experiences, it is expected to create a synergy effect in the process of acquiring indoor 3D data.