In 1980, Port and Harbour Research Institute (PHRI) constructed the first centrifuge (Mark I) with an effective radius of 3.8m. PHRI has conducted more than 1300 centrifuge operations on various research subjects. Since 1989, undesirable vibrations of the concrete pit floor have frequently occurred during the high speed operation, PHRI decided to construct a new centrifuge, namely Mark II, rather than repairing the Mark I Centrifuge.
　In 1989, PHRI started the construction of the new project which continued until 1994. The effective radius, maximum acceleration and maximum payload of the Mark II centrifuge are the same as the Mark I, however the control systems and safety systems have enormously improved to accommodate the 14 years' operation and experiences into the new facilities. And also the data acquisition system was totally replaced by advanced systems for the Mark II centrifuge.
　This report briefly reviews the summary of operation of the Mark I centrifuge and describes the development of PHRI Mark II centrifuge facilities.