One array antenna including three induction coils is formed on an application integrated circuit of a fixed housing. Eight array antennas, each of which is arranged in a manner similar to that of the array antennas of the application integrated circuit, are formed at intervals of 45 degrees around a rotation axis on an imaging process integrated circuit of a movable housing. A controller selects one of the eight array antennas of the imaging process integrated circuit so that a magnitude of a difference between a rotation angle of a movable housing and a rotation angle of the movable housing becomes equal to or smaller than 22.5 degrees based on the rotation angle of the movable housing, and controls a stepping motor so that a selected array antenna opposes to the array antenna on the application integrated circuit.