55. Which institution(s) receives financial reports from political parties and/or candidates?

Source: 
政治資金規正法, 1948 (2022改正)
Political Funds Control Act, 1948 (as amended by Act No.68 of 2022)

第十二条　政治団体の会計責任者は、毎年十二月三十一日現在で、当該政治団体に係るその年における収入、支出その他の事項で次に掲げるものを記載した報告書を、その日の翌日から三月以内に、第六条第一項各号の区分に応じ当該各号に掲げる都道府県の選挙管理委員会又は総務大臣に提出しなければならない。

第十四条　政党又は政治資金団体の会計責任者は、第十二条第一項の規定による報告書を提出するときは、あらかじめ、当該政党又は政治資金団体の党則、規約その他これらに相当するものに基づいて設けられた会計監査を行うべき者に対し、当該報告書に係る会計帳簿、明細書及び領収書等についての監査意見を求め、当該監査意見を記載した書面を当該報告書に添付するものとする。

Article 12. The accounting officer of a political organization shall, within three months from the day following December 31 of each year, submit a report to the prefectural election administration commission or the Minister of Internal Affairs and Communications, as specified in the respective items of Article 6, paragraph 1, based on the classification set forth in those items. This report shall detail the organization's income, expenditures, and other matters pertaining to that year as of December 31.

Article 14. When submitting a report pursuant to the provisions of Article 12, paragraph 1, the accounting officer of a political party or political funding organization shall, in advance, request an audit opinion from the person responsible for conducting the accounting audit established based on the party rules, bylaws, or other equivalent documents of said political party or political funding organization, regarding the accounting books, statements of details, receipts, and other documents pertaining to said report. The accounting officer shall attach a document containing said audit opinion to said report.

EMB, ministry, and auditing agency.

Financial reports should be submitted to election commissions or the Minister of Internal Affairs and Communications. They should be also submitted to an auditing agency first.