PURPOSE: To realize new transistor construction capable of operating at high speed without being influenced by the mobility of charge or limit of fine processing, by adopting 3-layer construction of a high-temperature superconductor, a normal conductor, and a high temperature superconductor.

CONSTITUTION: A normal conductor obtained by composition ratio change of Pr1Ba2Cu3O7 or YBCO, or a normal conductor or semiconductor 102 such as a compound semiconductor such as Si, GaAs, etc., is formed between high- temperature semiconductors 101 and 103 represented by Y1Ba2Cu3O7. And electrodes 104, 106, and 105 out of gold, silver, etc., are formed respectively on the surfaces of the high-temperature superconductors 101 and 103 and the normal conductor or semiconductor 102, and on these electrodes drawing-out electrodes are formed as an emitter E, the base B, and the collector C respectively. Incidentally, the width of 102 being a base region is 100nm or less. Accordingly, it becomes possible to realize a bipolar transistor easily capable of operating at high speed, a pico second or less.