PURPOSE: To enable the stable detection of the hot solution level of molten metal over a long period of time in a sensor fixed while holding current carrying performance even in the case of using ceramics excellent in corrosion resistance to high temperature molten metal as a sensor body part.

CONSTITUTION: A molten metal level detecting sensor has a sensor body part 1 brought into contact with or submerged in molten metal and a sensor holding means 2 for fittingly bonding the rear end of the body part 1 into a recessed part 4. In this case, a threaded hole 5 is provided at the outer side part of the recessed part 4 of the holding means 2, and a groove 3 is provided on the side peripheral surface near the upper end of the body part 1. The body part 1 is fitted into the recessed part 4 of the holding means 2 and screw-fastened so that the tip of a screw 7 reaches the groove part 3. Bonding can be performed by filling paste 8, excellent in current carrying performance, in a clearance between the end face of the recessed part 4 of the sensor holding means 2 and the upper face of the body part 1, or through a spring made of a heat resisting alloy, or further through a spring made of heat resisting alloy or metallic foil at the tip of the screw 7.