A safety device is provided, comprising an elastic membrane, which partially or completely delimits a hollow space, which is provided for the accident-initiated filling subject to elastic expansion of the membrane, and a gas generator with a filling fluid source communicating with the hollow space, wherein between the filling fluid source and a surface of the membrane facing the hollow space and/or in the membrane at least one heat protection means is arranged, which is provided for the protection of the membrane from a thermal impact through filling fluid of the filling fluid source.