公平交易法第十八條規定事業對於其交易相對人，就供給之商品轉售與第三人或第三人再轉售時，應容許自由決定價格，如有相反之約定者，依該條之規定，該約定無效，此規定係我國關於限制轉售價格之規範，該規範對限制轉售價格所採取之態度係絕對禁止，並無例外，與公平交易法其他規範設有例外規範之體例不同，就該規定即有研究之必要。 而公平交易法前開規定，其法條用語僅係表明事業對交易相對人其所供給之商品，應自由決定價格，有相反之約定者無效。但就違法之限制轉售價格之要件為何？即實施之限制轉售價格之行為主體為何？在關係企業間所實施之限制轉售價格之約定是否違反前開規定？限轉售價格之客體為何服務？是否得為限制轉售價格之客體？以及限制轉售價格之限制行為定義、態雄為何？等問題，並非僅觀察前開規定即可暸解，而須進一步研析。 因公平交易法前開絕對禁止其立法背景，在公平交易法立法時，該規定條採取原則禁止例外許可之規範形態，但在其後修法時，始成為現行絕對禁止之規範形態。故本文試就說明公平交易法第十八條立法沿革為始，進而參以各國學說及行政院公平交易委員會之見解，討論公平交易法第十八條所規範限制轉售價格之行為主體、客體及限制行為相關問題，以提供爾後執法機關及立法機關就執行該規範或修法時參考。

This paper deals with to broad categories of the Article 18 of the Fair Trade Law in Taiwan R.O.C., which regulates resale price restriction. This paper first discusses the history of Article 18 of the Fair Trade Law. Article 18 of the Fair Trade Law 2000 prohibits the restriction on resale. Before that, Article 18 of the Fair Trade Law 1992 allowed such resale price restriction on some consumer goods, but the Amendment of the Fair Trade Law 2000 repeals the exception clause. This paper secondly analyzed and discusses the elements of Article 18 to the Fair Trade Law. The beginning of this part investigates the relations between affiliated enterprises, and Article 18 of the Fair Trade Law. It also discusses the meaning of 'goods" of in Article 18 of the Fair Trade Law. The last part of this paper analyzes the meanings of the restriction of Article 18 of the Fair Trade Law and many different kinds of restriction.