A user seeking to transfer files, folders or other information to a second user can do so in a simple two-step process. An actuator carries a drive bushing onto which one end of a coil spring is mounted such that the axis of the coil spring is approximately parallel to the rotation axis of the actuator. Abutting portions, which protrude to the base side and are capable of abutting the base at the time of mounting, are provided on a bottom surface of the mounting plate that is an opposing surface to the base. The controller may include one or more control modes. The first reinforcing layer is wound around the inner tubular layer and the second reinforcing layer is wound around the first reinforcing layer. The gain-frequency characteristics of an IF signal which represents a beat signal between the transmission signal and a reception signal has its peak at or below one half of the sampling frequency of an AD converter.