A rotating device includes a communication unit including a transmitting portion having a first ring-shaped coil, a first ring-shaped magnetic body covering the first ring-shaped coil and a first terminal connected to the first ring-shaped coil, and a receiving portion having a second ring-shaped coil, a second ring-shaped magnetic body covering the second ring-shaped coil and a second terminal connected to the second ring-shaped coil, and a bearing connecting a hollow fixed portion to a hollow rotating portion, which is capable of rotating with respect to the fixed portion, in which the first ring-shaped coil and the second ring-shaped coil are formed so as to be wound around a rotation axis of the bearing, the first ring-shaped magnetic body and the second ring-shaped magnetic body face each other with a gap formed in the direction of the rotation axis, and the communication unit is provided inside the fixed portion and the rotating portion.