An apparatus, method, and medium of measuring skin hydration using a mobile terminal such as a cell phone are provided. The apparatus for measuring skin hydration, which is included in a mobile terminal, includes: a voltage applying unit which receives a power from a power source included in the mobile terminal, and applies a single power source voltage to a measuring portion a current measuring unit which measures a current flowing through the measuring portion where the voltage is applied a voltage amplifier which is input the measured current through a resistor, and amplifies a voltage across the resistor a control unit which controls an output voltage of the voltage amplifier to be in predetermined range and a calculating unit which calculates a susceptance of the measuring portion using the output voltage of the voltage amplifier, and calculates the skin hydration of the measuring portion using the calculated susceptance. Accordingly, skin hydration is measured using a single power source having a narrow voltage range used in a mobile terminal, so that a user can measure his or her skin condition at anytime and anyplace.