A heating cooker comprising: an optically-transparent top plate provided on a top face of the appliance; a heating unit formed in the top plate; an electrostatic touch key having an electrode, on a rear face of the top plate and used to instruct execution of a function assigned to the electrostatic touch key, the electrode being formed of a light-blocking conductive coating and having an optically-transparent cutting shape by removal of a part of the conductive coating; an operation detecting unit for applying an alternating current signal to the electrode and detecting a change in capacitance of the electrode with respect to a ground, the change being caused by a contact with a portion of the top plate facing the electrode; an operation unit light-emitting element for irradiating the electrode with light from a direction opposite to the top plate; and a light emission control unit for controlling light emission by causing the operation unit light-emitting element to be lit so that a shape of the electrode is visible through the top plate, and causing the operation unit light-emitting element to be unlit so that the shape of the electrode is less visible, characterized in that: after the appliance is powered on, the appliance is changed into a lock state in which only an operation inhibition releasing key among the electrostatic touch keys is operable, in the lock state, the light emission control unit causes only the operation unit light-emitting element of the operation inhibition releasing key to be lit, thereafter, operation of the operation inhibition releasing key brings the appliance into a state in which at least one of the electrostatic touch keys other than the operation inhibition releasing key is operable, and the light emission control unit causes the operation unit light-emitting element of the operable electrostatic touch key to be lit; and wherein the light emission control unit includes a lighting failure detecting unit for detecting a disconnection in a light source of the operation unit light-emitting element, and a display unit, and when the light failure detecting unit detects that the operation unit light-emitting element is not lit due to a failure, the display unit displays an error and informs a user of a lighting failure. an optically-transparent top plate provided on a top face of the appliance; a heating unit formed in the top plate; an electrostatic touch key having an electrode, on a rear face of the top plate and used to instruct execution of a function assigned to the electrostatic touch key, the electrode being formed of a light-blocking conductive coating and having an optically-transparent cutting shape by removal of a part of the conductive coating; an operation detecting unit for applying an alternating current signal to the electrode and detecting a change in capacitance of the electrode with respect to a ground, the change being caused by a contact with a portion of the top plate facing the electrode; an operation unit light-emitting element for irradiating the electrode with light from a direction opposite to the top plate; and a light emission control unit for controlling light emission by causing the operation unit light-emitting element to be lit so that a shape of the electrode is visible through the top plate, and causing the operation unit light-emitting element to be unlit so that the shape of the electrode is less visible, characterized in that: after the appliance is powered on, the appliance is changed into a lock state in which only an operation inhibition releasing key among the electrostatic touch keys is operable, in the lock state, the light emission control unit causes only the operation unit light-emitting element of the operation inhibition releasing key to be lit, thereafter, operation of the operation inhibition releasing key brings the appliance into a state in which at least one of the electrostatic touch keys other than the operation inhibition releasing key is operable, and the light emission control unit causes the operation unit light-emitting element of the operable electrostatic touch key to be lit; and wherein the light emission control unit includes a lighting failure detecting unit for detecting a disconnection in a light source of the operation unit light-emitting element, and a display unit, and when the light failure detecting unit detects that the operation unit light-emitting element is not lit due to a failure, the display unit displays an error and informs a user of a lighting failure. after the appliance is powered on, the appliance is changed into a lock state in which only an operation inhibition releasing key among the electrostatic touch keys is operable, in the lock state, the light emission control unit causes only the operation unit light-emitting element of the operation inhibition releasing key to be lit, thereafter, operation of the operation inhibition releasing key brings the appliance into a state in which at least one of the electrostatic touch keys other than the operation inhibition releasing key is operable, and the light emission control unit causes the operation unit light-emitting element of the operable electrostatic touch key to be lit; and wherein the light emission control unit includes a lighting failure detecting unit for detecting a disconnection in a light source of the operation unit light-emitting element, and a display unit, and when the light failure detecting unit detects that the operation unit light-emitting element is not lit due to a failure, the display unit displays an error and informs a user of a lighting failure.