Currently the Bureau of National Health Insurance will require employers of business with fewer than five workers to subscribe to coverage of the National Health Insurance according to ”the Highest Insured Payroll-Related Amount Applied to Their Employees” as referred to in Item 3, Paragraph 1, Article 41, in the Enforcement Rules of the National Health Insurance Act. Such action may have violated the authorization by the National Health Insurance Act and will hamper the development of small business. Under some assumptions, this article estimates potential extra burden of insurance premium that may be suffered by small business altogether to be in the range from 6.41 billion to 29.98 billion. Some suggestions of regulation amendment have been provided for more flexible treatments in order to promote the development of small business and its employment.