<p>This study examines the meaning of “the Democratic Regime of Government with the King as Head of State” by comparing between the 1949 and 1997 constitutions. One of the central concepts that form Thai politics is rabop prachathipatai an mi phramahakasat song pen pramuk, that is, Democracy with the King as Head of State (DKHS). Thai constitutions have been stipulating that Thailand is governed by a democratic system, and the king is the head of state. However, its exact wording has changed several times since the 1949 Constitution. The current expression of DKHS has been established since the 1991 Constitution.</p><p>DKHS has a long history of more than half a century as a constitutional and legal term; however, its meaning remains not clear. Historian Saichon Sattayanurak interpreted DKHS as the idea that when a political crisis arises, the king intervenes to resolve political disputes. Although it is a view with a certain degree of persuasive power, the myth that the king can intervene in a crisis and can attempt mediation has been completed after the bloody incident in May 1992. In contrast, the original wording of the DKHS first appeared in the 1949 Constitution.</p><p>This study hypothesizes that the meaning of DKHS has been changing along with changes in actual politics and elucidates changes in the meaning of the DKHS by comparing the drafting minutes of the 1949 Constitution, in which DKHS first appeared, and the 1997 Constitution, which was enacted after the 1992 Bloodshed. As a result of the examination in this paper, it became clear that at the time of the 1949 constitution, the DKHS was a means for the royalists to win the power struggle against the army and maintain the monarchy, however the 1997 Constitution, promulgated in an era of democratization, made it clear that the objects DKHS would control were the people and democracy to preserve the monarchy. Therefore, the meaning of DKHS has clearly changed along with changes in the political power struggle of the times.</p>