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

The grounds of appeal are examined.

1. According to the reasoning of the lower judgment and the record, the following facts are revealed.

On October 25, 2013, the Defendant publicly announced a bid for entrusted management services of the instant facilities in order to select a private business entity to be entrusted with the operation, maintenance, management, etc. of the resource recovery facilities and ancillary facilities (hereinafter “instant facilities”).

As a result of the bidding, the joint contractors consisting of four companies in E, F, and G (hereinafter collectively referred to as "Plaintiffs, etc.") were selected as successful bidders by making the plaintiff the representative.

Accordingly, joint contractors of the plaintiff et al. and the defendant entered into an agreement on the entrusted operation of the facility of this case.

(hereinafter “instant agreement”). (b)

The main contents of the instant agreement are as follows.

(1) The expenses for entrusted operation shall be classified into the expenses for settlement of accounts and the expenses for settlement of accounts (transfer expenses) and shall be paid monthly under a contract with the total annual amount.

Expenses for settlement of accounts are all expenses incurred in medicine expenses and expendable materials expenses, such as chemical drugs, inspection agency expenses, facility maintenance expenses, fuel expenses, analysis and medical expenses, power expenses, water supply expenses, LNG charges, and other expenses incurred in the business conducted at the request of the defendant. The expenses for settlement of accounts are all expenses, such as labor expenses and expenses, excluding the settlement expenses.

(Article 9.1.2. (2) (2) Where taxes and public charges are changed (Article 9.1.1.1.1.2. (2), where there is any change in the relevant laws and regulations and facilities (Article 9.1.1.1.2), or where there is any change in the relevant laws and facilities (Article 9.2.2), or where there

(3) The settlement of expenses for entrusted operation shall be made once a year, and the performance shall be settled by the end of January of the following year until the end of each fiscal year.

(4) The plaintiff et al. shall assign a certain number of persons with specific qualifications required under relevant laws and regulations to the site of the instant facilities, and the operating personnel shall be 42 persons, but the number of persons may be adjusted to the extent that does not interfere with stable operation.