Code of Civil Procedure Article 63
An intervener may not dispute the correctness of the decisions made in the action against the supported party, except where the intervener has been denied a means of attack or defense either due to the phase of the litigation at the time of the intervention or by an act of the party supported, or where the supported party has willfully or through gross negligence failed to employ certain means of attack or defense unknown to the intervener.The provisions of the preceding paragraph shall apply mutatis mutandis to the case where the supported party asserts the same dispute against the intervener.
中文原文 民事訴訟法第63條
參加人對於其所輔助之當事人，不得主張本訴訟之裁判不當。
但參加人因參加時訴訟之程度或因該當事人之行為，不能用攻擊或防禦方法，或當事人因故意或重大過失不用參加人所不知之攻擊或防禦方法者，不在此限。
參加人所輔助之當事人對於參加人，準用前項之規定。
但參加人因參加時訴訟之程度或因該當事人之行為，不能用攻擊或防禦方法，或當事人因故意或重大過失不用參加人所不知之攻擊或防禦方法者，不在此限。
參加人所輔助之當事人對於參加人，準用前項之規定。