In 1947, the Constitution of ROC was promulgated and put into effect. Then in 1949, the "Investigation Bureau of the Ministry of Interior" was established in Kuanchew to complete and strengthen what is an integral part of law enforcement in a constitutional government. That was the beginning of MJIB. It was the first government investigation agency ever legalized in this country. Mr. Ji Yuan-Fo was assigned to be the first Director General, and in Dec. of the same year the Bureau was relocated along with ROC government to Taipei, Taiwan. Another reorganization took place on June 1st, 1956. At that time the Bureau was renamed the "Investigation Bureau of Ministry of Judicial Administration". Afterwards the Bureau started to take up major investigation & internal security issues concerning national safety and violation against national interests. In the wake of the 1955 transformation, Mr. Ji was retained at the head office. On August 1st, 1980, owing to the renewal the R.O.C.'s judicial systems, the Bureau was given its present, permanent title, "MJIB".Since October 30, 1998, the MJIB function has been redefined, by an Executive Yuan decree, in the following nine items that cover crime-prevention and investigation.
MJIB conducts investigations on information indicating potential espionage & its activities and how it may affect political stability, financial order and social peace. It gather intelligence on the transforming and developing of local partisans and factions that adversely affect administration and provincialism, as well as the state of "peace & order" during elections, in which vote-buying and violence are singled out. It monitors high-profile movements, including unlawful gathering or parades, major petitions, complaints illegal, demonstrations or contingencies that affect peace and order. Investigations conducted on racketeers, concealed weapons among triads, smuggling & drug-trafficking and triad supporters.
Maintaining internal security is one of the major functions of MJIB. Maintaining national secrets is the equivalent of safeguarding national security. In pursuance to the "Organization Provision of MJIB", the Bureau is responsible for investigation and internal security involving the offenses of treason, sedition and other violations endangering national security interests. In other words, to safeguard national security is of primary importance and this is followed by maintaining national interests, and protecting the people's well-being are among the rest of the functions of the Bureau. Counter-espionage and infiltration are the cornerstone for security and stability. Indications and evidence obtained from intelligence and past cases of this Bureau verify that enemy espionage agents on certain occasions have sneaked into Taiwan island under legal, as well as other illegal covers. They are suspected of various methods of information collection, prowling, stealing technology, disrupting economic and social order. In this regard, the Bureau makes an effort, besides a full grasp of general situations, in planning and placing tactile preparations to dig out clues for effective countermeasures. In dealing with enemy espionage, all-out support and participation are called for from various sectors of society.The ROC government passed rudimentary legislation of opium-related offenses of the "Criminal Code." Later on, in the reinforced legislations enacted to strengthen control, and to impose additional penalties upon drug-use and its spread the following laws were enacted: the "Ordinance of Eliminating Illicit Drugs"; the "Narcotics Control Statute." MJIB, pursuant to its duties mandated by law, has taken charge of the task of wiping out illicit drugs & narcotics.