A well temperature-controlled Thermally Stimulated Depolarization Current (TSDC) apparatus is constructed. The structure of electrodes and the assembly of the measuring-chamber are shown and explained. The direct welding of a sheath micro-heater and a cooling pipe to one of the electrodes permits excellent control of sample temperature at heating, cooling and isothermal processes. The high performance of the apparatus is demonstrated by showing a result of TSDC measurement of an aromatic polycarbonate.