A wireless communication device comprising: a radiation conductor base material including a radiation conductor and having a principal surface on which the radiation conductor is provided; and a radio frequency integrated circuit, RFIC, element having a principal surface on which a terminal electrode is formed, wherein the RFIC element is affixed to the principal surface of the radiation conductor base material with an adhesive material so that the terminal electrode faces the radiation conductor , and wherein the radiation conductor entirely overlaps with the terminal electrode in a planar view of the radiation conductor base material, characterized in that the RFIC element has an RFIC chip processing a high-frequency signal, a power feeding circuit having a resonance frequency corresponding to a communication frequency, and a substrate having the RFIC chip mounted thereon and the power feeding circuit built therein; the terminal electrode is formed on a principal surface of the substrate and connected through the power feeding circuit to the RFIC chip ; substrate has a flexible base material, and the RFIC chip and the terminal electrode do not overlap with each other in the planer view; a rigid region and a flexible region are formed in the RFIC element , wherein a region where a first terminal electrode , a second terminal electrode , and the RFIC chip are disposed is a rigid region, and the other region is a flexible region; and the first terminal electrode and the second terminal electrode are each disposed at a position away from the RFIC chip in a planar view so that the flexible region are formed between the first terminal electrode and the RFIC chip and between the second terminal electrode and the RFIC chip . a radiation conductor base material including a radiation conductor and having a principal surface on which the radiation conductor is provided; and a radio frequency integrated circuit, RFIC, element having a principal surface on which a terminal electrode is formed, wherein the RFIC element is affixed to the principal surface of the radiation conductor base material with an adhesive material so that the terminal electrode faces the radiation conductor , and wherein the radiation conductor entirely overlaps with the terminal electrode in a planar view of the radiation conductor base material, characterized in that the RFIC element has an RFIC chip processing a high-frequency signal, a power feeding circuit having a resonance frequency corresponding to a communication frequency, and a substrate having the RFIC chip mounted thereon and the power feeding circuit built therein; the terminal electrode is formed on a principal surface of the substrate and connected through the power feeding circuit to the RFIC chip ; substrate has a flexible base material, and the RFIC chip and the terminal electrode do not overlap with each other in the planer view; a rigid region and a flexible region are formed in the RFIC element , wherein a region where a first terminal electrode , a second terminal electrode , and the RFIC chip are disposed is a rigid region, and the other region is a flexible region; and the first terminal electrode and the second terminal electrode are each disposed at a position away from the RFIC chip in a planar view so that the flexible region are formed between the first terminal electrode and the RFIC chip and between the second terminal electrode and the RFIC chip . <EOS>