A subscriber terminal holding a subscriber identity is connected to a sub-terminal using the identity of the subscriber terminal over a wireless proximity interface. The three X-ray generating units are arranged so as to make an angle formed by a first X-ray exposure direction and a second X-ray exposure direction on a rotational plane thereof be a same angle as that formed by the second X-ray exposure direction and a third X-ray exposure direction on the rotational plane, the same angle being smaller than 120 degree. Each of the source drivers generates a pulse signal after receiving the corresponding frame data to activate the next source driver.