An ear jack for detecting an earphone plug is provided. The ear jack includes a housing, a plurality of pins, a first detection part, a second detection part, and a controller. The housing includes a cavity for inserting terminals of the earphone plug. The plurality of pins are installed on an inner circumference surface of the housing and are in selective contact with a corresponding terminal of the earphone plug. The first detection part detects insertion of a first terminal of the earphone plug. The second detection part detects the insertion of the first terminal. The controller detects the insertion of the earphone plug when the first detection part and the second detection part both detect the insertion of the first terminal.