Anti-theft device configured to be attached to merchandise to be protected, preferably to cardboard boxes, comprising: • a housing, which comprises a winding apparatus rotatably arranged therein, • at least one securing-loop arrangement, which comprises one or more securing loops, each having at least one securing cord connected to the winding apparatus, the securing cords being windable onto the winding apparatus in response to a rotational winding movement of the winding apparatus, and being unwindablefrom the winding apparatus in response to a rotational unwinding movement of the winding apparatus, the securing-loop arrangement being designed and intended to loop around the merchandise to be protected such that the anti-theft device can be securely connected to the merchandise to be protected, and • a locking mechanism, which is accommodated at least in part in the housing and is operatively connected to the winding apparatus, the locking mechanism having an unlocked state, in which the rotational unwinding movement of the winding apparatus in the housing is permitted, and a locked state, in which the rotational unwinding movement of the winding apparatus in the housing is prevented, the locking mechanism further comprises a release element, which is made at least in part of a shape-memory alloy and is configured to cause the locking mechanism to be transferred from the locked state to the unlocked state when the shape-memory alloy is in an excited state, characterized in that the locking mechanism is further configured so as to permit the rotational winding movement of the winding apparatus when the locking mechanism is in the unlocked state and when the locking mechanism is in the locked state. • a housing, which comprises a winding apparatus rotatably arranged therein, • at least one securing-loop arrangement, which comprises one or more securing loops, each having at least one securing cord connected to the winding apparatus, the securing cords being windable onto the winding apparatus in response to a rotational winding movement of the winding apparatus, and being unwindablefrom the winding apparatus in response to a rotational unwinding movement of the winding apparatus, the securing-loop arrangement being designed and intended to loop around the merchandise to be protected such that the anti-theft device can be securely connected to the merchandise to be protected, and • a locking mechanism, which is accommodated at least in part in the housing and is operatively connected to the winding apparatus, the locking mechanism having an unlocked state, in which the rotational unwinding movement of the winding apparatus in the housing is permitted, and a locked state, in which the rotational unwinding movement of the winding apparatus in the housing is prevented, the locking mechanism further comprises a release element, which is made at least in part of a shape-memory alloy and is configured to cause the locking mechanism to be transferred from the locked state to the unlocked state when the shape-memory alloy is in an excited state, characterized in that the locking mechanism is further configured so as to permit the rotational winding movement of the winding apparatus when the locking mechanism is in the unlocked state and when the locking mechanism is in the locked state.