The National Security Bureau (NSB; Chinese: 國家安全局; pinyin: Guójiā Ānquán Jú) is the principal intelligence agency of Taiwan.

Though a few known intelligence failures of the National Security Bureau have surfaced in recent years, supporters have pointed out that the agency rarely, if ever, publicizes any successful operations.

[5] In 2004, former US State Department Deputy Assistant Secretary Donald W. Keyser was arrested by the FBI for illegally handing over documents to two Taiwanese NSB officials who served as intelligence liaison officers in USA.

Traditionally, career personnel of law enforcement, intelligence agencies, and military organizations in Taiwan are labeled as pan-blue because most of them have been lifelong Kuomintang members.

In 2004, Chen Feng-lin (陳鳳麟), a colonel of the logistics department, Special Service Center, National Security Bureau, confessed[7] that he leaked classified information regarding security measures at President Chen Shui-bian's residence as well as the president's itinerary to Peng Tzu-wen (彭子文), a former director of the center who retired as a major general.

In August 2005, Peng Tzu-wen was indicted[8] for leaking national secrets on TV and for potentially putting Chen's life in jeopardy.

Traditionally, the successive bureau chiefs were exclusively military officers with the rank of three-star general, though this has changed in recent years.