第二百六十四条（徴税吏員の道府県法定外普通税に関する調査に係る質問検査権）
Article 264Power of Tax Collection Officials to Question and Inspect in Investigations Concerning Prefectural Non-Statutory Ordinary Tax
If necessary for an investigation concerning the assessment and collection of prefectural non-statutory ordinary tax, a prefectural tax collection official may question the persons listed below, or inspect books and documents relating to the business of a person listed in items (i) through (iii) (including, where electronic or magnetic records (meaning records made in electronic form, magnetic form or any other form not recognizable by human perception, which are used for information processing by a computer) have been made or kept in lieu of making or keeping them, those electronic or magnetic records; the same applies in items (i) and (ii) of paragraph (1) of the following Article) or other articles, or request the presentation or submission of those articles (including copies thereof):
道府県の徴税吏員は、道府県法定外普通税の賦課徴収に関する調査のために必要がある場合においては、次に掲げる者に質問し、又は第一号から第三号までの者の事業に関する帳簿書類（その作成又は保存に代えて電磁的記録（電子的方式、磁気的方式その他の人の知覚によつては認識することができない方式で作られる記録であつて、電子計算機による情報処理の用に供されるものをいう。）の作成又は保存がされている場合における当該電磁的記録を含む。次条第一項第一号及び第二号において同じ。）その他の物件を検査し、若しくは当該物件（その写しを含む。）の提示若しくは提出を求めることができる。
a person liable for tax or a person found to have tax liability;
納税義務者又は納税義務があると認められる者
a person found to have an obligation to give money or goods to a person listed in the preceding two items;
前二号に掲げる者に金銭又は物品を給付する義務があると認められる者
a person other than those listed in the preceding three items who is found to be directly related to the assessment and collection of that prefectural non-statutory ordinary tax.
A successor corporation in a company split (meaning a corporation that has had assets and liabilities transferred to it by a splitting corporation in a company split; the same applies hereinafter in this paragraph) in a company split in which a person listed in item (i) or (ii) of the preceding paragraph is the splitting corporation (meaning a corporation that has transferred its assets and liabilities through a company split; the same applies hereinafter in this paragraph), and a splitting corporation in a company split in which a person listed in item (i) or (ii) of the preceding paragraph is the successor corporation in a company split, are included in the persons found to have an obligation to give money or goods prescribed in item (iii) of that paragraph.
In the case referred to in paragraph (1), the tax collection official in question must carry an identification card certifying the official's status and present it when requested by a person concerned.
A prefectural tax collection official may, as provided by Cabinet Order, retain the articles submitted pursuant to the provisions of paragraph (1).
Investigations concerning delinquent tax collection procedures for prefectural non-statutory ordinary tax are governed by the provisions of Article 285, paragraph (6), notwithstanding the provisions of paragraph (1).
道府県法定外普通税に係る滞納処分に関する調査については、第一項の規定にかかわらず、第二百八十五条第六項の定めるところによる。
The authority of a prefectural tax collection official under paragraph (1) or (4) must not be construed as having been granted for the purpose of a criminal investigation.
略称規定第十条の四第二項
第四条第三項の規定により課する普通税（以下「道府県法定外普通税」という。）若しくは第五条第三項の規定により課する普通税（以下「市町村法定外普通税」という。）又は第四条第六項若しくは第五条第七項の規定により課する目的税（以下「法定外目的税」…
わかりやすく言うと
道府県が、地方税法に定める税目のほかに、別に税目を起こして課する普通税のことです（第四条第三項）。