Intake apparatus for internal combustion engine

An intake apparatus including two intake ducts and a flap mechanism disposed in one of the two intake ducts, the flap mechanism including a main flap, a damper flap, a damper chamber cooperating with the damper flap to form a damper space, and a biasing member biasing the main flap in a closing direction. When the main flap is located in an angular range between the fully closing position and a predetermined opening angle, a peripheral edge of the damper flap is opposed to an inner wall surface of the damper chamber with a fine clearance to thereby render the damper space substantially closed. When the main flap is located with an opening angle larger than the predetermined opening angle, a communication passage to open the damper space is formed between the inner wall surface of the damper chamber and the peripheral edge of the damper flap.