A planar irradiating coil including a first ring conductor, a second ring conductor having a smaller diameter than that of the first ring conductor, and a plurality of first line conductors that connects the first ring conductor and the second ring conductor, is provided with means for causing the irradiation pulse to be more uniform. That is, in order to make the irradiation pulse more uniform, it is necessary to disperse the operating voltage or to diverge the irradiation current. Therefore, the irradiating coil is provided with a plurality of resonant capacitance elements on the first ring conductor between its connections with the first line conductors, or it is provided with second line conductors, that are connected to the first line conductors, and third line conductors, that connect each end of the second line conductors with the second ring conductor.