PURPOSE: To prevent an electromagnetic wave from being reflected from an iron tower, a bridge, etc., by covering conductive bars, which are constituents of the iron tower, the bridge, etc., with a ferrite cylinder to enhance impedance.

CONSTITUTION: Reflection prevention unit 1 which is arranged around iron pipe 2 consists of semicylindrical ferrite half bodies 3 and 4 which can unite with each other, and conductive foil 5 such as aluminum foil is fitted to the inside circumference face of unit 1. Since the surface impedance becomes high because materials having a high electromagnetic wave absorption characteristic are used as the ferrite forming ferrite half bodies 3 and 4, the current is flowed little, and as a result, the reflected electromagnetic wave is reduced. It is sufficient for this reflection prevention unit if the circumference of conductors of the iron tower, the bridge, etc., is surrounded by the ferrite which has a high electromagnetic wave absorption characteristic, and the form of this unit may be selected properly as desired.