Since the power consumption of a concave turbine was thought to be the same as that of the Rushton turbine, it had not previously been studied. In this work, the power consumption of a concave turbine in a flat cylindrical vessel was measured, and the power number of the impellers could be correlated with the modified equations of Kamei et al. (1995, 1996). The power number of the concave turbine with baffle was found to be half that of the Rushton turbine.