Basic Code Governing Central Administrative Agencies Organizations Article 29

The Executive Yuan shall define the functions of ministries in accordance with the provisions listed in the following subparagraphs:1. In line with the core functions of central administrative agencies, each ministry shall perform policy integration and coordination functions.2. Basic policies or similar functions shall be undertaken by the same ministry; conflicting or balancing functions shall be performed by different ministries.3. A balance shall be maintained between the policy functions and authority of each ministry.The number of ministries shall be limited to 15.
中文原文 中央行政機關組織基準法第29條
行政院依下列各款劃分各部主管事務:
一、以中央行政機關應負責之主要功能為主軸,由各部分別擔任綜合性、統合性之政策業務。
二、基本政策或功能相近之業務,應集中由同一部擔任;相對立或制衡之業務,則應由不同部擔任。
三、各部之政策功能及權限,應儘量維持平衡。
部之總數以十五個為限。

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