A wheel circuit using electromagnetic induction and an electronic pen are provided. The wheel circuit includes a rotary encoder configured to be rotated according to a user operation and includes at least one port, a resonant unit configured to be coupled with a port of the at least one port, and at least one capacitor including one end which is coupled with at least one other port which is not coupled with the resonant unit among the at least one port. The at least one capacitor has a capacitance different from each other, wherein at least one other capacitor of the at least one capacitor is connected to the resonant unit according to rotation of the rotary encoder to vary a resonant frequency.