An exemplary embodiment of the present invention provides a stylus pen including: a body portion; a conductive tip configured to be exposed from an inside of the body portion to an outside thereof; a ground portion configured to be electrically connected to a user; and a resonant circuit portion in the body portion, electrically connected between the conductive tip and the ground portion, and including one or more resonance circuits that resonate with electrical signals of different frequencies transferred from the conductive tip to output resonance signals of different frequencies.