Although arbitration is a contractual method of dispute settlement but it has a judicial output. This output emerged from imposing the arbitrator's award on disputing parties. The entry of the arbitrator into the arbitration process requires the establishment of a contractual relationship between him and the parties to the dispute. The agreement which is concluded by the disputers to obligate the arbitrator to settle the dispute is called the "Arbitrator's Contract". This contract, which is considered less, at least in Iran's law, is the source of the arbitrator entry into the process of arbitration and his intervention in resolving the dispute. According to this contractual relationship arbitrator obligate to settle the dispute between disputers. In contrast, disputing parties also obligate to pay remuneration. The main practice of this research is to analyze the unknown relationship from the contract law perspective. An implicit assumption of the issue is twofold, firstly, men of parties in this pattern must be specified and then to check whether the issue and entity or the nature of that correlation can be applicable to the preset contract forms of civil law or it is a new separate design. Results from the analysis of relationship between arbiter and disputing parties reveals that at least three involved agents must meet the same state of mind on the case, which discusses unraveling issues in return of specified wage and finally this contract has its own nature and aspect.