To allow changing, adding and removing of a roller, making smooth the rotation of a swivel base, and also reduce a swivel surface wearing of the roller by considering the balance of weight and an off-center status of mounted articles.

A mounting base with a swivel mechanism 1 comprises a fixing base 2 placed directly on a floor, a swivel center axis 3 mounted on the fixing base 2, a swivel board 5 held in rotary, a plurality long bolts 6, a plurality of rollers 7 and a swivel base 8, then the swivel base 8 is rotated by an arbitrary angle while being supported by the plurality of rollers 7 rotating on the fixed base 2. The swivel mechanism is composed of the bolts 6 screwed radially on the board 5 and with the roller 7 screwed respectively to the bolts 6, and adjusts the numbers and the positions of the bolts 6 and the rollers 7 mounted to the mechanism according to the weight and the off-center status of mounted articles.