The judgment of the court below is reversed.

The first instance judgment is revoked, and the case is remanded to the Seoul Administrative Court.

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. According to the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents (hereinafter “Urban Improvement Act”), in cases where there is a difference between the price of land or building previously owned by a person who purchased a site or building and the price of the site or building that was sold to him/her, a project implementer shall collect or pay an amount equivalent to the difference (hereinafter “settlement money”) from the person who purchased the site or building from the person who purchased the site or building, or pay the difference to the person who purchased the site or building (the main sentence of Article 57(1)), and the difference between the

(Article 61(1). In addition, if a person who is liable to pay the settlement money fails to pay it or fails to pay the dues, the project executor who is not the head of Si/Gun may entrust the collection thereof to the head of Si/Gun who is not the head of Si/Gun, and the entrusted head of Si/Gun may collect it in the same manner as delinquent local taxes are collected, and in this case the project executor shall deliver the amount equivalent to 4/

(1) Article 58(1) and Article 61(4) and (5) of the Act on the Maintenance and Improvement of Urban Areas (hereinafter “Urban Areas, etc.”) provides a simple and economic special remedy procedure that enables a project implementer to entrust the collection of liquidation money and dues (hereinafter “settlement money, etc.”) in the same manner as delinquent local taxes are collected, the collection shall, in principle, be based on the relevant procedure: Provided, That in special circumstances, such as where the head of a Si/Gun does not comply with the entrustment of collection, a project implementer, who is not the head of a Si/Gun, may directly file a claim against the owners of land, etc. for the payment of liquidation money, etc.,