The order on Friday said that Akaradej was to be moved to the Royal Thai Police's Operations Centre, and Maj-General Charn Wimolsri, deputy commander of the Central Investigation Bureau, be made caretaker CSD commander.
The order stated that the transfer was made in order to create more efficiency and smooth operations.
The transfer was expected as rumours of such have circulated since last week.
Police spokesman General Dejnarong Suttich-arnbancha said the national police chief made the decision based on suitability reasons.