PURPOSE: To determine the value of an overvoltage and to perform means for overcoming it by connecting a diode to be conducted by an overvoltage between an input terminal connected to the internal element of a semiconductor integrated circuit and a ground potential, and a fuse to be melted by the overvoltage in series.

CONSTITUTION: A protective resistor 4 is connected from an input terminal 1 to an internal element 2, and a diode 5 and a fuse 6 connected in series are inserted between the terminal 1 and a GND. The diode 5 is conducted when an overvoltage V is applied to the terminal 1. The fuse 6 is melted when a voltage of the overvoltage or more is applied. Thus, after a semiconductor integrated circuit is damaged, if a package is opened and the disconnecting state of the fuse is confirmed, the magnitude of the overvoltage can be presumed, or determined in a limited range to search a cause for damaging the circuit and means for solving it can be desirably performed.