The judgment of the court below stated as follows on the ground that the defendant's disposition of selling the forest land to the plaintiff was unlawful and explained as follows: the defendant sold the forest land to the non-party first, and the plaintiff paid in full and acquired ownership of the same object before he acquired ownership. Thus, the defendant's double sale disposition against the plaintiff, which became effective, is not a serious and obvious defect, but a double sale disposition against the plaintiff is merely a case where it can be cancelled for this reason, but it is not a case based on an unjust means, such as the plaintiff's coercion of fraud, but a double sale disposition against the plaintiff. The defendant's double sale disposition against the plaintiff, which became a result of the employee's error, was not merely based on the employee's work error, and the forest land was sold to the non-party for a long time after the lapse of the period of time after the plaintiff's appeal, and it cannot be a ground for revocation under related laws such as the Act on the Disposal of Property Belonging to Which the plaintiff belongs and the Act on Special Measures for the Disposal of Property Belonging to Which the plaintiff belongs.

However, as long as the defendant legally sold the property devolving upon the non-party to the non-party, the non-party should have acquired the right as a purchaser of the property devolving upon the acquisition of ownership by making a full payment of the price for the property devolving upon the non-party. Thus, if the defendant neglected the non-party's right and again sold the real estate to the plaintiff, and completed the registration of transfer of ownership, this does not constitute an unlawful administrative disposition infringing upon the non-party's right. Since such unlawful administrative disposition can be revoked at any time, it is legitimate for the defendant to revoke the disposition of double sale of the property devolving upon the plaintiff on the ground that it is legitimate for the defendant to revoke the disposition of double sale of the property devolving upon the above ground, it is erroneous that the court below erred in holding that the disposition of cancellation was unlawful on the ground that the judgment was just, and the judgment of the court below is reversed and remanded to Seoul High Court for further proceedings. It is so decided as per Disposition by the assent of all participating Justices.

Justices of the Supreme Court (Presiding Judge) Mag-kim Kim-bun and Magman