A sheet-type metamaterial to operate in a terahertz wave band, comprising: a film-shaped dielectric substrate; a first wire array formed on one surface of the dielectric substrate; and a second wire array formed on an opposite surface of the dielectric substrate, wherein the first wire array includes elongated metallic first cut wires of a predetermined length I aligned in a direction of a first axis of the dielectric substrate with a gap g therebetween and in a second axis direction perpendicular to the first axis with space s therebetween, the second wire array includes second metallic cut wires having the same shape as the first cut wires and aligned so as to overlap the first cut wires, the first cut wire and the second cut wire (11 a) each having a long axis extending substantially parallel to the first axis direction, the length I of the first cut wires and the second cut wires is set in a range from about 20 to about 320 μm, and wherein with a wavelength λ at a usable frequency, the length I of the first cut wires and the second cut wires is about λ/2, wherein the usable frequency is set in a range from 0.3 to 0.9 THz, the width w of the first cut wires and the second cut wires is set in a range from about 46 to about 50 μm, the space s is set in a range from about 160 μm to about 162 μm, and a thickness d of the dielectric substrate is set between about 50 μm to about 23 μm, or wherein the usable frequency is set in a range from 1.0 to 3.0 THz, the width w of the first cut wires and the second cut wires is set in a range from about 5 to about 46 μm, the space s is set in a range from about 16 to about 162 μm, and the thickness d of the dielectric substrate is set between about 50 μm to about 23 μm. a film-shaped dielectric substrate; a first wire array formed on one surface of the dielectric substrate; and a second wire array formed on an opposite surface of the dielectric substrate, wherein the first wire array includes elongated metallic first cut wires of a predetermined length I aligned in a direction of a first axis of the dielectric substrate with a gap g therebetween and in a second axis direction perpendicular to the first axis with space s therebetween, the second wire array includes second metallic cut wires having the same shape as the first cut wires and aligned so as to overlap the first cut wires, the first cut wire and the second cut wire (11 a) each having a long axis extending substantially parallel to the first axis direction, the length I of the first cut wires and the second cut wires is set in a range from about 20 to about 320 μm, and wherein with a wavelength λ at a usable frequency, the length I of the first cut wires and the second cut wires is about λ/2, wherein the usable frequency is set in a range from 0.3 to 0.9 THz, the width w of the first cut wires and the second cut wires is set in a range from about 46 to about 50 μm, the space s is set in a range from about 160 μm to about 162 μm, and a thickness d of the dielectric substrate is set between about 50 μm to about 23 μm, or wherein the usable frequency is set in a range from 1.0 to 3.0 THz, the width w of the first cut wires and the second cut wires is set in a range from about 5 to about 46 μm, the space s is set in a range from about 16 to about 162 μm, and the thickness d of the dielectric substrate is set between about 50 μm to about 23 μm.