An earphone is disclosed. The earphone comprises an external auditory meatus insertion member, a casing and a driver unit. At least a part of the external auditory meatus insertion member is insertable into an external auditory meatus. The external auditory meatus insertion member is attached to the casing. The driver unit is disposed within the casing to generate sounds. The casing includes a front space formed in front of the driver unit, a sound guide hole in communication with the front end of the front space to cause sounds to impinge on the external auditory meatus, and a rear space formed in the rear of the driver unit.