To prevent an assembling top from injuring a person with a spindle, and also damaging tatami mats (thick straw mats that cover the floor) or the like even when the top is rotated on the tatami mats or a carpet.

The assembling top includes: a right circular conic trapezoidal body 11; the spindle 13 to be the rotary axis of the body 11; and a balance ring 15 for preventing the eccentric rotation of the body 11 to be rotated with the spindle 13 as a center. The body 11 includes a hole 12 in the center of axle at the side of a top surface 11a, where the spindle 13 is inserted so as to be removable. A ring shape recession 14 is also arranged in a peripheral edge part at the side of a bottom surface 11b, where the balance ring 15 is removably fitted. The spindle 13 has a spherical surface at the tip end.