A wireless IC device that is operable in a wide band and is suitable for RFID systems includes a radiating plate and an electromagnetically coupled module constituted by a wireless IC that processes transmitted/received signals and a feeding circuit board having a feeding circuit and coupled with the wireless IC. The radiating plate includes a linear electrode bent at a bent portion and apparently sectioned into two linear electrode portions having different lengths. The electromagnetically coupled module is arranged such that the feeding circuit board and the linear electrode portions are electromagnetically coupled. The wireless IC is operated by signals received by the radiating plate, and response signals from the wireless IC are radiated outward from the radiating plate.