To provide a molten metal sensor which is improved in such a manner that the remaining of burrs is prevented so as not to emit erroneous signals.

A chamfer is provided at a corner part formed by the face 3g of a holder 3 in contact with a molten metal and the outer circumferential face 3h of the holder 3 in contact with a die 11. Further, a chamfer is provided at a corner part formed by the face 3g of the holder 3 in contact with the molten metal and the inner circumferential face (a part of a recessed hole 3b) of the holder 3 in contact with an insulator 2.