A wireless tag includes a circuit module having an electromagnetic induction unit for generating an electromotive force by an electromagnetic wave of the outside and an information storing unit for storing information and outputting the information by the electromotive force, a base part on which the circuit module is disposed and which is foldable, and a locking member provided in the base part which electrically cuts off the electromagnetic induction unit in case that the base part is folded and locks the base part in the folded state. Further, the wireless tag includes a belt for attaching the circuit module to an object. The base part is folded with the belt disposed between its both sides and thus the belt becomes a ring shape. In addition, the locking member of the wireless tag is disposed near the information storing unit and has a projection part projecting from the base part and a base side insertion part into which the projection unit is inserted, and the belt has a hole into which the locking member is inserted in case of being disposed between both sides of the base part.