Other resonators similar in shape to itself, with a partially open structure of a closed curve line, arranged opposite itself. A closed-curve line is formed between the resonator, which uses electromagnetic coupling to transfer high-frequency power in a non-contact manner, and the drive unit causes the resonator to rotate in the circumferential direction of the resonator in the plane of the Transfer of high-frequency power between a resonator and another resonator at multiple locations where the angles in the circumferential direction are different from each other and transmitted from one resonator to the other that is detected at each position of the resonator. Control to set the angle at which this transfer of high-frequency power is carried out based on the power value of the high-frequency power that was set. A resonance device comprising a part.