In order to design a low-noise multiblade fan, there have been earnest demands for detailed analysis of the flow pattern between the fan blades. However, the flow between the fan blades is unsteady and three-dimensional in nature, thus it is too complex to analyze theoretically. In the present study, a spark tracing method was employed to visualize the detailed three-dimensional flow between fan blades at a high speed. A Petchan prism and drum camera were used to convert the rotational images observed from the axial and radial directions into static ones, enabling visualization of the three-dimensional flow between the blades for a desired blade cross section.