An electromagnetic field control member includes an insulating member constituted of a cylindrical ceramic and having a plurality of through holes along an axial direction, a conductive member constituted of metal and closing the through holes so as to provide an opening that opens in an outer periphery of the insulating member, and a power supply terminal connected to the conductive member. The power supply terminal is located away from an inner wall of the insulating member forming the through holes, and has a first end and a second end in the axial direction, and at least one of the first end and the second end is located farther away from the inner wall than a central portion of the power supply terminal.