Abstract: A safety box comprises a multi-layered wall having provided therein at least one conductor, which responds by interruption or short-circuiting to damage caused to the wall, and which, if the wall is damaged, activates a circuit connected to said conductor. In response to activation of said circuit, documents contained in said safety box are marked or destroyed via an ignition means. The wall of the safety box is provided with electric shield means. In order to increase the response reliability of the circuit, the invention provides the feature that the shield means is galvanically separate from the circuit.