To judge normal or defective of a sample easily, quickly, accurately, and automatically through operation with the aid of digital coordinate data of characteristic curve.

This device is used to judge normal or defective of a sample by measuring the characteristic curve of the sample and comparing it with the reference characteristic curve that is stored in advance. The reference characteristic curve is converted in advance into digital coordinate data at n measuring points of (XR1, YR1) to (XRn, XRn) and stored, while the measured characteristic curve is converted into digital coordinate data at n measuring points of (XM1, XM1) to (XMn, XMn) and stored, then the total sum S of the absolute values of respective differences of the X values and Y values are totalled. The judgement value based on the total sum S and the preset limit value are compared with each other in size, and the judgment result is outputted according to the obtained comparison result as a result.