A folding anchor impeller was developed for a round-bottomed flask with a small neck, which is frequently used for research and development of new materials and technologies in the laboratories of industries and universities. The power consumption and mixing time were measured over a wide range of Reynolds number and compared with those obtained for two traditional types of impellers for relatively high viscous liquids in a round-bottomed flask and those calculated for a helical ribbon impeller set in a cylindrical vessel. It was found that the power correlation developed for paddle impellers in a spherical agitated vessel was also applicable for data obtained for the folding anchor impeller, The power consumption for the folding anchor impeller was much higher than those of two traditional impellers, but almost the same with that for a double helical ribbon impeller, On the other hand, the mixing time for the folding anchor impeller was less than one-fifth those obtained for two traditional impellers, and it was comparable to that calculated for a helical ribbon impeller according to the correlation, Consequently, the folding anchor impeller needs the lowest mean energy dissipation rate to attain the same mixing time among the impellers considered in this work.