Disclosed is an earphone, which includes a housing defined with a first sound hole, a second sound hole, and a resonant cavity communicating the first sound hole and the second sound hole inside the housing; and a loudspeaker in the resonant cavity, having a first sound emitting surface corresponding to the first sound hole, and a second sound emitting surface facing the first sound emitting surface, where sound emitted from the second sound emitting surface pass to the second sound hole through the resonant cavity.