Air intake apparatus for internal combustion engine

An air intake apparatus for an internal combustion engine includes a casing (C) including an intake port (G) and a discharge port (H), a rotary valve (E) rotatable around a rotational axis (X) within the casing (C) and including a valve element (4) that controls a connecting state between the intake port (G) and the discharge port (H), and an inner surface forming portion (13) formed at an inner surface (12) of the casing (C) along the rotational axis (X) of the rotary valve (E) and defined from the intake port (G) to the discharge port (H), a distance of the inner surface (12) from the rotational axis (X) being shorter than a maximum rotational radius (R) of the valve element (4).