The present invention provides an earphone, comprising an earphone housing, a speaker cover, a sound emitting tube, and a speaker, wherein the earphone further includes a tuning baffle disposed inside the speaker cover, wherein a sound emitting hole, a sound outlet hole and mode slots are disposed on the speaker cover, and the sound emitting tube is connected to the tuning baffle through the sound emitting hole, a mode protrusion and a tuning hole are disposed on the tuning baffle, and the mode protrusion is limited by different mode slots by rotating the tuning baffle via the sound emitting tube, so as to adjust the sound outlet area of the sound outlet hole. By utilizing the above-mentioned invention, it is possible to adjust the mid-bass frequency response of the earphone so that a single type earphone can exhibits different sound characteristics.