Basic characteristics of the electronic devices are able to figure out from V-I characteristics. We built up the analysis system that was able to measure V-I characteristics of the elemental devices, in order to find the basic characteristic, the semiconductor junction characteristics, and the inner structures. Before designing of the system, we deliberated about high accuracy circuit, and tried to build up it. After this, we tried to apply this system to measuring the diodes and transistors, and tested the capability of this system. Conformation of the diodes and transistors differ a little from one to another, because of applications. Characteristics of conformation difference are able to be determined from V-I characteristics. From the V-I characteristics of the diodes and transistors, it was got a gratifying result of the semiconductor junction characteristics.