This study investigated the concept images of blind students about the polygon concept. For this purpose, four open-ended questions were asked to five blind middle school students. During the interviews, geometric shapes were presented with raised-line materials and blind students were given opportunities to construct geometric shapes with magnetic sticks and micro-balls. Qualitative research techniques applied in grounded theory were used for analyzing documents pictures, which were taken from magnetic geometric shapes that blind students constructed, raised-line materials and researchers' observation notes and interviews. As a result, it is determined that blind students have more than one concept image for the polygon concept. They scrutinized the polygon concept analytically not with a holistic perspective. They were often conflicted about triangle, rectangle, square, circle and circular region whether or not being a polygon. They also encountered with the difficulties associated with the combination of polygon sides' endpoints consecutively.