Our objects are to determine physiological mechanisms controlling the shoot regrowth with storage starch degradation by amylases during initial regrowth of phasey bean. Plants were grown and transferred into the controlled environmental chamber set at 200℃ on 30℃ （low on high temperature pretreatment: LTP and HTP, respectively）. After an 8-day adjustment period, all plants were defoliated and grown at 25℃. Amylase activities and carbohydrate concentrations in stems and roots were compared on day 0, 1, 3, and 6 after defoliation. Starch contents at defoliation and the consumption during regrowth were higher in LTP than in HTP. As the result, new shoot production during initial 6 days was five-fold higher in LTP than in HTP, indicating the importance of the carbohydrate utilization for regrowth. Although a-amylase activity showed almost the same level between LTP and HTP, the higher starch degradation in LTP than in HTP was observed during the first 1 day. Between day 1 and 3, a-amylase activity was elevated due to a sink demand in LTP. The disappearance of the increase in a-amylase activities between day 3 and 6 may be cause by the depletion starch but likely not by the weakening demand in sink organs.