ANTENNA COIL UNIT

The antenna coil unit includes a main coil and an auxiliary coil electrically insulated from the main coil, the auxiliary coil being arranged at a position in which an induction current is produced by a magnetic field produced by an electric current flowing through the main coil. The auxiliary coil is configured in a state in which a frequency deviating by a predefined amount in a predefined direction from a target frequency predefined within a harmonic component of the fundamental component of an electromagnetic wave produced by the electric current flowing through the main coil is taken as a resonance frequency. The direction and amount are such that the phase of an alternating-current current flowing through the auxiliary coil is in an opposite-phase state, which is opposite the phase of the harmonic component of an AC current flowing through the main coil.