To cope with the warming global environments, greenhouse gas emission should be reduced in the electric power generation. The hydroelectric power should occupy the attention of the electric power generation systems, as clean and cool energy sources with the highest density. The authors have proposed the counter-rotating type hydroelectric unit, and discussed the fundamental performances and the flow conditions. This paper discusses the effects of the blade profiles on the hydraulic performances. As a result, the design materials for the solidity of the axial flow runners suitable for the given water circumstances are induced from above discussions.