PURPOSE: An earphone device and an operation method thereof are provided to improve the usage convenience of a device by deactivating a corresponding function when an earphone is separated from an ear. CONSTITUTION: An earphone device(120) comprises a cable(121). An ear jack(124) is installed in one end of the cable. The ear jack is inserted into an ear jack hole(111). The ear jack hole is included in a device which has a sound or an image playback function. An earphone(122) is installed in the other end of the cable. The earphone comprises a speaker unit. The speaker unit is inserted within the inner ear of a user. An illuminance sensor(123) is installed in the earphone.
