The judgment below is reversed, and the case is remanded to Busan High Court.

The grounds of appeal are examined.

1. The reasoning of the lower judgment reveals the following facts.

(1) On June 30, 2003, A Co., Ltd. (hereinafter “A”) concluded the instant construction contract with the Defendant Association for the reconstruction project promoted by Defendant B Apartment Reconstruction Project Association (hereinafter “Defendant Association”).

Defendant C, Defendant D, etc., an executive of the Defendant Union, jointly and severally guaranteed the obligations of the Defendant Union under the said construction contract.

(2) Article 4(1) of the Construction Contract of this case provides that the construction method of the instant construction contract concluded by the Defendant Union as “A” and “A” shall be “a final share swap.” Article 4(2) of the Construction Contract of this case provides land to B and the members of the Plaintiff, which is supplied as a substitute for the apartment and auxiliary welfare facilities newly built in return for the provision of land B. The land “B” refers to the land in a state that does not interfere with the commencement of construction work of B by securing the ownership of the land and the right to use the land and securing the right to use the land.” Article 4(2) of the Construction Contract of this case provides that “B shall include the necessary project expenses according to the design plan approved by the head of the competent local government, terms of the contract, etc., with the construction of the building facilities and newly built apartment and auxiliary welfare facilities under the conditions for payment for the land provided by the Plaintiff.” Article 4(3) of the Construction Contract of this case provides that “The remaining building site shall be sold to the general public and its construction expenses shall belong to the members.