On 4 human subjects, perception of the movement velocity of the fused auditory image (FI) was studied by means of click-train dichotic stimulation with gradually changing interaural time delays. With the signal used, the subjects were able to perceive differences in the velocities of FI movement. Absolute velocity difference limens (DL) were determined on the assumption that FI movement was uniform and that its trajectory might be approximated by an arc of a circle. The velocity DL were nearly linearly related to the velocity of FI movement and increased from 10.8.degree. to 19.3.degree. s with increases of the velocity of FI movement from 14.degree./s to 140.degree./s.