In an intake control device, upper and lower partition plates are provided in an intake passage extending obliquely upward from a combustion chamber as seen in an axial direction of a crankshaft. The partition plates divide the intake passage into upper intake passages and lower intake passages. A tumble control valve is arranged in an upstream vicinity of the partition plate in the intake passage. The tumble control valve opens or closes the upper intake passage. A bottom wall, which is a portion of a wall around an inlet of the lower intake passage and positioned on the side opposite to the upstream partition plate, is inclined to be gradually separated from the upstream partition plate as it extends upward.