A micro-wave oven, comprising: a case body, which comprises a heating house; a master control board disposed in the case body; a magnetic field generation component and a magnetic field induction component disposed in the heating house, wherein the magnetic field induction component is electrically connected with the master control board; and the master control board is configured to detect, according to a magnetic field change signal, whether there is a metal object entering or being removed from the heating house, characterized in that, said magnetic field induction component is a magneto-resistive sensor; wherein the magnetic field induction component is configured to collect the magnetic field change signal of a magnetic field generated by the magnetic field generation component; wherein the magnetic field change signal represents a speed direction and speed magnitude of a metal object; when a magnetic field intensity of the magnetic field change signal increases or decreases gradually, the master control board is configured to determine that there is a metal object entering the heating house, and not to respond to a heating instruction triggered by a user; and the master control board is further configured to cache the heating instruction triggered by the user; when a direction characteristic in the magnetic field change signal is opposite to that in the magnetic field change signal collected when the metal object enters the heating house, the master control board is configured to determine that there is a metal object being removed from the heating house, and to respond to the cached heating instruction triggered by the user; the micro-wave oven further comprises: a reset button; when detecting that the reset button is pressed, the master control board is configured to determine that the metal object is removed from the heating house, and to respond to the cached heating instruction triggered by the user. a case body, which comprises a heating house; a master control board disposed in the case body; a magnetic field generation component and a magnetic field induction component disposed in the heating house, wherein the magnetic field induction component is electrically connected with the master control board; and the master control board is configured to detect, according to a magnetic field change signal, whether there is a metal object entering or being removed from the heating house, characterized in that, said magnetic field induction component is a magneto-resistive sensor; wherein the magnetic field induction component is configured to collect the magnetic field change signal of a magnetic field generated by the magnetic field generation component; wherein the magnetic field change signal represents a speed direction and speed magnitude of a metal object; when a magnetic field intensity of the magnetic field change signal increases or decreases gradually, the master control board is configured to determine that there is a metal object entering the heating house, and not to respond to a heating instruction triggered by a user; and the master control board is further configured to cache the heating instruction triggered by the user; when a direction characteristic in the magnetic field change signal is opposite to that in the magnetic field change signal collected when the metal object enters the heating house, the master control board is configured to determine that there is a metal object being removed from the heating house, and to respond to the cached heating instruction triggered by the user; when a magnetic field intensity of the magnetic field change signal increases or decreases gradually, the master control board is configured to determine that there is a metal object entering the heating house, and not to respond to a heating instruction triggered by a user; and the master control board is further configured to cache the heating instruction triggered by the user; when a direction characteristic in the magnetic field change signal is opposite to that in the magnetic field change signal collected when the metal object enters the heating house, the master control board is configured to determine that there is a metal object being removed from the heating house, and to respond to the cached heating instruction triggered by the user; the micro-wave oven further comprises: a reset button; when detecting that the reset button is pressed, the master control board is configured to determine that the metal object is removed from the heating house, and to respond to the cached heating instruction triggered by the user.