Abstract: A rotary contactless connector and a non-rotary contactless connector enable data transmission in a contactless mode by optical elements by combining a rotary transformer or a stationary transformer and a means for coupling the optical elements, and providing a power system with or without a buffer feature by a storage means to receive supplied electric power. The rotary contactless connector has a rotary transformer (1), a light emitting element (8) or a light receiving element provided in the rotor (3), and a stationary light emitting element or light receiving element (11). Data is transmitted between the light emitting element (8) and the light receiving element (11) while supplying electric power to the rotor (3) through the intermediary of the rotary transformer (1).