In order to provide a small air-intake apparatus for an internal combustion engine, which can satisfactorily control an air flow and can reduce energy loss in a rotary valve, the air-intake apparatus includes a surge tank; a first air-intake passage communicating with the surge tank; a second air-intake passage communicating with the surge tank; a casing including a first port connected to the first air-intake passage, a second port connected to the second air-intake passage, and an outlet port connected to an air-intake portion of the internal combustion engine; a rotary valve including a rotor housed in a valve casing portion of the casing to be rotatable about a rotational axis, the rotary valve being configured to control air intake directed to the air-intake portion by rotation of the rotor; and a first seal for sealing between the rotor and a surface of the valve casing portion facing the rotor with at least either one of the first port, second port and outlet port being closed.