PURPOSE: To obtain an apparatus having simple construction and easy fabrication and to detect surely the surface of a molten metal and the breaking of wire by providing a thermosensitive element in the neighborhood of a ladle and fetching a signal of this thermosensitive element to a thermometer having setting device.

CONSTITUTION: A thermoelectric thermosensitive element 11 is attached to a holder 6 provided to a supporting arm 2 and a contact 12 is placed at a position capable of contacting with the surface of a molten metal 4. For example, the contact 12 is made of thin cast iron and has high sensitivity and thermoelectromotive force generating member made of highly sensitive chromel-alumel (CA) is used for the thermoelectric thermosensitive element 11. The element 11 is connected to a temperature indicator having a setting device 13 by a CA compensation lead wire 14 having a little smaller resistance for transmitting the thermoelectromotive force. This temperature indicator 13 is incorporated in e.g. a control board arranged near a dicast machine main body. The temperature indicator 13 adopts a burnout construction and the temperature is raised by the breaking of wire.