PURPOSE: To provide a method for reducing radio-wave reflection at low cost with excellent ghost preventing effect without causing restriction on an outer design nor increasing the weight of an outer-wall panel.

CONSTITUTION: A reinforcing bar 2 is partly covered with a ferrite core 1 made of Ni-Zn-, Mn-Zn- or MgZn-based material and embedded in a reinforced concrete. A high-frequency current flows through the reinforcing bar 2 when the radio-wave reaches there, but the ferrite core 1 functions as a resistor against the high-frequency current. Then, the reinforcing bar 2 is put in an isolated state electrically at the part that is covered with the ferrite core 1 so that an interaction between a radio wave and the reinforcing bar 2 is prevented, and thereby ghosts caused by a reflected wave can be prevented.