The present invention discloses an automatic semiconductor device classification system including a current measuring unit, a data memory, a processor connected to the data memory and the current measuring unit, and an output unit connected to the processor. Patterns of curves representing approximate I-V characteristics between predetermined electrodes of semiconductor devices are automatically determined and the approximate I-V characteristics are classified into predetermined categories. The data memory stores the discrete I-V relations, and further stores a first control voltage, a first threshold current value at the first control voltage, a second control voltage corresponding to the second control voltage. The processor includes an acquisition circuit, a comparison circuit and a classification circuit. In the acquisition circuit, the first decision current value at the first control voltage and the second decision current value at the second control voltage are obtained using the measured results. In the comparison circuit, the first decision current value is compared with the first threshold current value stored in the data memory and the second decision current value is compared with the second threshold current value stored in the data memory. In the classification circuit, the patterns of the curves representing the approximate I-V characteristics are determined and classification is performed.