To improve the balance of weight between the right and the left in a rotating body.

In a yo-yo the rotating body 1 of which is provided with disks 2, 3, a coupling body 4 for coupling the disks 2, 3, and a bearing 5 mounted on a part located between the disks 2, 3 on the coupling body 4, the disk 2 is provided with a light and sound emitting device 7 including a switch 12, a battery 13, light sources 14, 15, and a speaker 16 on a circuit board 11, and the disk 3 is provided with a light emitting device 8 including a switch 22, a battery 23, and light sources 24, 25 on a circuit board 21. A light and sound emitting device including the switch 22, the battery 23, the light sources 24, 25, and a speaker which is not shown in the figure and corresponds to the speaker on the circuit board 21 may be provided on the disk 3 as a substitute for the light emitting device 8 to emit light and a sound from the disks 2, 3.