An earphone, comprising a rear housing, a front housing, and a loudspeaker unit which divides a cavity formed by the rear housing and the front housing into a front and rear acoustic cavities; wherein the earphone further comprises a sound adjusting element; the front housing is provided with a sound outlet hole and mode posts, and the sound adjusting element is provided with a sound adjusting hole corresponding to the sound outlet hole and a mode adjustment groove corresponding to the mode posts; when the sound adjusting element rotates, the mode adjustment groove may be limited by different mode posts, thus adjusting the volume of the front acoustic cavity and the area of a sound hole for the front acoustic cavity. Use of the above-described invention enables the middle and high frequency responses of the earphone to be adjusted and enables a single earphone to provide different sound characteristics.