A blade of rotor with the type NACA-64 was tested with a low-speed test blower. Certain special techniques were applied to the measurements of the blow condition, namely, the measurements of pressure distribution on rotating blades and the measurement using a yaw meter which rotates with the rotor, etc. The measured blade-element performance was compared with the performace estimated from cascade data over a broad range of the incidence angles. As a result of this investigation, the turning and deviation angles of the rotor were found to agree with cascade data in the region of the annulus free from wall boundary-layer effects. The wake from upstream of the rotor causes the separation of the flow on the blade surface at a flow rate larger than the undisturbed flow. When the wake goes out through the rotor, the low-energy air of the wake experiences a greater turning than that of the main stream.