A method of producing a radio frequency member to construct a radio frequency confinement device based on a waffle iron structure includes providing an intermediate work of a plate shape or a block shape, the intermediate work including a main surface which is shaped as a plane or a curved surface and a plurality of rods extending away from the main surface. An interval between a side surface of one of the plurality of rods and a side surface of another rod that is adjacent to the one rod monotonically increases in a direction away from the main surface. The method also includes forming an electrically-conductive plating layer on the main surface and at least the side surface of the plurality of rods by immersing at least a portion of the intermediate work in plating solution.