Abstract: On one side of a passageway for an identification subject 10 with an IC tag 7 to pass, an antenna is provided for reading information stored in the IC tag 7, and a front wave-absorbing wall 2 and a rear wave-absorbing wall 3 are provided protruding from the vicinity of the front and rear edges of the antenna 8 toward the passageway 13 such that the walls narrow the half-power angle ? of the radio wave radiated from the antenna 8 over a horizontal plane. A wave-absorbing side wall 1 is also provided on the other side of the passageway 13. With such a structure, the propagation area of the radio wave can be controlled so that the reading area of the IC tag 7 can be limited, and the influence of the reflected wave is suppressed.