PURPOSE: To enable a highly unexpected interesting movement to be enjoyed by comparing the size of signals inputted to a sensor with a comparator to rotate forward and backward a motor with the output of the comparator for operating a decoration device.

CONSTITUTION: The output ends of R and L microphones 41 and 43 are connected respectively to the input ends of R and L amplifiers 45 and 47 to amplify the outputs of the microphones in the amplifiers 45, 47. The amplified signals are inputted to R and L comparators 49 and 51 to be compared, while the output signals are inputted to a reversible motor driving circuit 53 to controllably rotate a motor 55. The motor is rotated in the direction of larger input signal to pivot a rotor of a decoration device. R and L stop switches 57 and 59 connected to the reversible motor driving circuit 53 control the pivotable range of the rotor 2. Thus, when a decoration is mounted on the rotary decoration device and one calls to the decoration, the decoration turns to him.