The judgment below is reversed, and the case is remanded to the Seoul Central District Court.

The grounds of appeal are examined.

1. Even if the extinctive prescription of a guaranteed obligation is not completed due to reasons such as suspension of the extinctive prescription, where the extinctive prescription of the principal obligation is completed, the principal obligation is extinguished due to the completion of the extinctive prescription, and thus, the guaranteed obligation also ceases to exist naturally

However, where there are special circumstances to deny the subsidiary nature of the guaranteed obligation, the surety cannot claim the extinguishment of the guaranteed obligation on account of the lapse of the prescription period of the principal obligation (see, e.g., Supreme Court Decision 2010Da51192, Jul. 12, 2012). However, in order to deny the subsidiary nature that falls under the essential nature of the guaranteed obligation by recognizing special circumstances, the surety has expressed his/her intent to perform the guaranteed obligation despite the lapse of the prescription period of the principal obligation, or agreed with the obligee. Only the fact that the surety provided the cause for the lapse of the prescription period of the principal obligation cannot be denied.

2. The court below acknowledged the following facts based on evidence. A.

On March 5, 2004, the Defendant concluded a loan business agreement with financial institutions, such as Seoul Mutual Savings Bank (hereinafter “Seoul Mutual Savings Bank”), to lend part payments to buyers, to build and sell the instant commercial building, and the Defendant jointly and severally guaranteed the obligations of buyers to the Seoul Mutual Savings Bank.

B. A became the principal obligor of each of the instant loans by obtaining a loan from the Seoul Mutual Savings Bank as the buyer on August 13, 2004 and September 1, 2004 or acquiring the status of the buyer on April 5, 2006 and acquiring the status of the buyer on April 5, 2006.

C. From July 28, 2005, the Defendant extended the maturity of the intermediate payment of the instant commercial buildings to the Seoul Mutual Savings Bank every six months.