In this paper the optimum distribution of circulation is examined and from which a designing method of the submerged hydrofoil is proposed. In § 2 a calculating method for obtaining the distribution of chord length and attack angle over the span of the submerged hydrofoil with a prescribed distribution of circulation is considered in detail. In § 3 the expression is introduced for the resistance of arbitrary distribution of circulation and the relation between both resistance, induced and wave-making, is discussed in the extremely high Froude number. In § 4 applying the variational method, it is verified that the optimum distribution of circulation can be obtained in such case that the induced velocity is constant over the span under the effect of free surface. At the same time a practical method for calculating the optimum distribution of circulation is shown. In § 5 the wave motion is examined and it is shown that the surface disturbance peculiar to the submerged hydrofoil of finite span exists in the vicinity of the hydrofoil and is caused by both vortex motions, free and bound. In § 6 the numerical examples are shown of optimum distribution of circulation, distribution of chord length and attack angle over the span of the designed hydrofoil and surface disturbance for two Froude numbers.