A person who is to be subject to adjudication may intervene in proceedings for adjudication of domestic relations.
審判を受ける者となるべき者は、家事審判の手続に参加することができる。
A person other than a person who is to be subject to adjudication, but who is to be directly affected by the outcome of adjudication or who is eligible to be a party, may intervene in proceedings for adjudication of domestic relations with permission from the family court.
審判を受ける者となるべき者以外の者であって、審判の結果により直接の影響を受けるもの又は当事者となる資格を有するものは、家庭裁判所の許可を得て、家事審判の手続に参加することができる。
A family court may, when it finds it to be appropriate, by its own authority, have a person who is to be subject to adjudication and the person prescribed in the preceding paragraph intervene in proceedings for adjudication of domestic relations.
家庭裁判所は、相当と認めるときは、職権で、審判を受ける者となるべき者及び前項に規定する者を、家事審判の手続に参加させることができる。
The provisions of paragraph (3) of the preceding Article apply mutatis mutandis to an application for intervention under the provisions of paragraph (1) and a petition for permission for intervention under the provisions of paragraph (2).
When a person who is to intervene in proceedings for adjudication of domestic relations under the provisions of paragraph (1) or (2) is a minor, and when the family court finds that the person's interests would be harmed by having the person intervene in the proceedings for adjudication of domestic relations in consideration of the person's age, degree of development, and all other circumstances, the family court must dismiss the application for intervention filed under the provisions of paragraph (1) or the petition for permission for intervention filed under the provisions of paragraph (2).
An immediate appeal may be filed against a judicial decision to dismiss an application for intervention filed under the provisions of paragraph (1) (including a judicial decision to dismiss an application for the intervention filed under the provisions of paragraph (1) pursuant to the preceding paragraph).
A person who intervenes in proceedings for adjudication of domestic relations pursuant to the provisions of paragraphs (1) through (3) (hereinafter referred to as an "interested party intervenor") may perform the procedural acts that may be performed by a party (excluding the withdrawal of or amendment to a petition for adjudication of domestic relations and the withdrawal of an appeal against a judicial decision or of an objection to a disposition by a court clerk); provided, however, that, with regard to the filing of an appeal against a judicial decision and of an objection to a disposition made by a court clerk, the interested party intervenor may perform the act only when the intervenor is eligible to do so pursuant to the other provisions of this Act concerning the filing of an appeal or of an objection.
第一項から第三項までの規定により家事審判の手続に参加した者（以下「利害関係参加人」という。）は、当事者がすることができる手続行為（家事審判の申立ての取下げ及び変更並びに裁判に対する不服申立て及び裁判所書記官の処分に対する異議の取下げを除く。）をすることができる。ただし、裁判に対する不服申立て及び裁判所書記官の処分に対する異議の申立てについては、利害関係参加人が不服申立て又は異議の申立てに関するこの法律の他の規定によりすることができる場合に限る。
Read this with the articles around it
procedural actmachine translation
「手続行為」
An act a person performs in the proceedings of a domestic relations case (家事事件).
Short name set inArticle 17, paragraph (1)
interested party intervenor
「利害関係参加人」
A person who has joined proceedings for adjudication of domestic relations (家事審判) under Article 42, paragraphs (1) to (3) — as a person who is to be subject to the ruling, or, with the family court's permission or by its order, as a person directly affected by its outcome or qualified to be a party — and who may then perform most of the procedural acts a party can.
Short name set inArticle 42, paragraph (7)