From the standpoint of lifting-line theory, the wall effect of tank side is considered on the lift and resistance of the submerged hydrofoil of finite span. The main results obtained are as follows (1) The lift increases and the resistance decreases due to the wall effect, but those amounts are comparatively small. (2) A correcting method for the wall effect is proposed. (3) A minimum allowable breadth of the experimental tank for neglecting the wall effect should be more than twice span of the submerged hydrofoil. (4) Some special cases are examined and compared with the previous results.