An insert earphone which prevents a sound leakage and improves wearing comfort. An ear chip has a barrel portion and first and second annular flange portions having the shape of a parabola spreading from the top toward the middle and from the middle toward the base of the barrel portion respectively. The first annular flange portion has a smaller outer diameter than the second annular flange portion. The first annular flange portion has almost even thickness from the inner circumference to the outer circumference, and has the inner circumference neighborhood substantially formed in the shape of a sliced doughnut.