Code of Civil Procedure Article 86

An intervener shall bear the expenses incurred for the intervention. Notwithstanding, the opposing party shall still bear the litigation expenses imposed in accordance with the provisions of Articles 78 to 84 inclusive.The provision of the preceding article shall apply mutatis mutandis to the case where the claim of the action must be adjudicated jointly with regard to the intervener and the supported party.
中文原文 民事訴訟法第86條
因參加訴訟所生之費用,由參加人負擔。
但他造當事人依第七十八條至第八十四條規定應負擔之訴訟費用,仍由該當事人負擔。
訴訟標的,對於參加人與其所輔助之當事人必須合一確定者,準用前條之規定。

English translation for reference only; the Chinese text prevails. Not legal advice.