Liquid velocity and direction were measured by an electrochemical probe. The probe had three microelectrodes, and the two-dimensional direction and velocity were calculated from a cross-correlation function of the voltage fluctuations. Measurements were done in a rotating basin, and the most suitable values of parameters-the distance between the electrodes and the time span of calculating the cross-correlation function-were decided. This probe can be constructed cheaply, and it can be used in dilute aqueous solutions of sodium chloride (0.01 M) and also mediums for cultivation of microorganisms without employing commonly used electrolytes such as ferricyanide.