PURPOSE: To prevent the damage of a logic circuit part of an IC even if erroneously inserted and connected by sealing a unidirectional conductive element in the package of the IC together with a logic circuit IC chip.

CONSTITUTION: When the positive and negative of the polarity of a voltage to be applied to an IC is erroneously applied to a terminal 3 with negative voltage and to a terminal 8 with positive voltage, the junction between the emitter and base of the transistor 6 of a protecting circuit 2 is reversely biased, causing the transistor 6 to be cut off, with the result that the current flowing between the emitter and the collector of the transistor becomes zero. Therefore, reverse po- larity is not applied between the lines A and B at both ends of the logic circuit 1, and many transistors of the logic circuit 1 can be avoided from being damaged.