A contactless data carrier which is adapted to be disposed in a receiving portion of an object connection device includes a base and a tag member. The base is adapted to be tucked into the receiving portion and has an upper section and a lower section, which are connected to each other. An outer peripheral surface of the base is adapted to abut against an inner surface of the receiving portion. A width of the upper section gradually decreases in a direction away from the lower section. A width of the lower section gradually decreases in a direction away from the upper section. The tag member is disposed at the base is stored with data relative to the object connection device to be read in a contactless manner by a reading device.