An apparatus and method for preventing erroneous detection of a jack is provided. The apparatus includes a detection terminal configured to detect whether a jack plug of an earphone is inserted into the jack, a comparator configured to compare a voltage input from the detection terminal with a predetermined reference voltage and provide a comparison result signal to a baseband module, a resistor with a certain resistance value, being interposed between the detection terminal and the comparator to keep a voltage of a high signal not to be lowered than the predetermined reference voltage when the jack is conducted due to conductive particles flowed into the jack.