Coil apparatus for use in transcranial magnetic stimulation apparatus

A coil device for use in a transcranial magnetic stimulation device that has a coil provided so as to face the surface of the head of a human, and stimulates neurons by producing an electric current from an induced electric field in a magnetic stimulation target region inside the brain as a result of electromagnetic induction, the coil device being equipped with a coil configured by winding a conductive wire along a prescribed reference surface, and a magnetic body that: is positioned so as to face the coil and be opposite the head from the coil with the coil sandwiched therebetween; has an electric current flowing therethrough from an induced electric field when the coil is driven; and increases the electric current from the induced electric field that flows through the magnetic stimulation target region of the brain as a result of the electric current produced by the induced electric field, in comparison to when no magnetic body is present.