Code of Civil Procedure Article 58
A third person who is legally interested in an action between two parties may, for the purpose of supporting one of them, intervene in the action while it is pending.Intervention may occur jointly with appeals from judgments, appeals from rulings, or any other act of litigation. A third person who is legally interested in a final and binding judgment in an action between two parties and who has intervened in such action, may initiate a rehearing action for the party supported.
中文原文 民事訴訟法第58條
就兩造之訴訟有法律上利害關係之第三人，為輔助一造起見，於該訴訟繫屬中，得為參加。
參加，得與上訴、抗告或其他訴訟行為，合併為之。
就兩造之確定判決有法律上利害關係之第三人，於前訴訟程序中已為參加者，亦得輔助一造提起再審之訴。
參加，得與上訴、抗告或其他訴訟行為，合併為之。
就兩造之確定判決有法律上利害關係之第三人，於前訴訟程序中已為參加者，亦得輔助一造提起再審之訴。