The present study investigated unsteady characteristics of a swirling jet. The experimental facility was designed to control a swirl ratio which is the ratio of the averaged swirl velocity at the trailing edge of the impeller to the averaged axial velocity at the slot. The swirl ratio was adjusted by varying the rotational speed of the impeller and the mass flow rate. The swirling jet was visualized by smoke and a laser sheet. The visualization result showed that the swirling jet at the high swirl ratio leaned to the outside wall and flowed radially. The fluctuating circumferential velocities were measured by hot wire probes. By Fast Fourier Transform (FFT), it confirmed that the three cells rotated in the same direction as the rotating direction of the impeller. At higher swirl velocity ratios, the normalized frequencies of the rotating cells were not changed by the swirl velocity ratio. On the other hand, at lower swirl ratios, the normalized frequencies of the rotating cells increased with the decrease of the swirl ratio. The unsteady characteristics of the swirling jet observed in the experiment were simulated by the computation fluid dynamics (CFD) well.