This paper intends to identify experimentally the relationship between transverse vibration behavior of a spinning disk and high-frequency fluctuation in the driving torque. A testrig has been developed using a CD-ROM disk, a driving motor with torque-varying capability and a power transmission belt and a laser vibrometer was employed to measure the transverse vibration displacements of the disk for a certain range of the spinning speed. The results show that the spinning speed and the magnitude and frequency of the torque fluctuation affect the stability of the disk. In other word, the torque fluctuation causes the instability of the disk at several ranges of the spinning speed below the critical speed and its effects become larger as the disk spins faster or the magnitude of torque fluctuation becomes bigger. The experimental results are found to be in good agreement with analytical estimation.