An earphone, comprising an earphone housing and a loudspeaker unit accommodated in the earphone housing, the loudspeaker unit dividing a cavity formed by the earphone housing into an earphone front sound cavity and an earphone rear sound cavity; wherein the earphone further comprises a tuning mechanism; wherein a rear sound cavity audio hole is provided on the loudspeaker unit rear sound cavity, and the loudspeaker unit rear sound cavity is in communication with the earphone rear sound cavity through the rear sound cavity audio hole; the tuning mechanism is provided between the rear sound cavity audio hole and the housing, and the tuning mechanism is used to adjust the size of the rear sound cavity audio hole of the loudspeaker unit. The present application allows for individual adjustment of the sound quality of the earphone in accordance with a middle and low frequency requirements of different users.