A radio frequency (RF) trap for a superconducting magnet apparatus includes an electromagnetic wave shield which includes a conductive shield member and is configured to surround an electric cable; and a circuit member which is provided in a portion of the electromagnetic wave shield, and includes a conductor circuit electrically connected to the conductive shield member in at least two positions. Two positions at which the conductive shield member is electrically connected to the conductor circuit are selectively adjusted so that a current path of the conductor circuit is adjustable according to the two positions at which electrical connections are made.