In this paper we propose an image-based mosaic generation system using traditional mosaic patterns which adaptably assigns the mosaic patterns according to the properties of image region. We first segment an input image based on a regularity and directional similarity. Then, we assign an appropriate pattern to each segment using three traditional patterns, which are commonly used in an ancient art. Since our mosaic system effectively mimics a traditional mosaic making, we can stylize an image similar to the hand-made mosaic without any user intervention.