In this study, the expandable shale collected from the same area in Korea is fired to confirm the foamability. The firing uses an electric furnace capable of firing up to 1600 ℃. The shale was classified into three types according to its constituent and apparent characteristics, and each component was analyzed by XRD analysis method. The shale was fired considering the firing temperature and the residence time. As a result of firing, it was found that the firing temperature was different by more than 100 degrees and it was confirmed that the foaming property was increased with increasing temperature