PURPOSE: To provide a liquid level measuring instrument utilizing an induction type level gauge which can be calibrated without fluctuating the surface level of liquid metal contained in a container, equipment, etc., nor receiving any restriction from the calibrating time even when the surface level of the liquid metal is not at the self-calibrating point of the liquid gauge.

CONSTITUTION: A liquid level measuring instrument is constituted of an induction-type level gauge 2 housed in a protective pipe 5 wound with a primary coil 3 for excitation and secondary coil 4 for detection, inner guide pipe 6a which houses the gauge 2, outer guide pipe 7 which is put on the outside of the pipe 6a and has an equalizing port 8 at its bottom, and pressure adjusting means 10, 11, and 13a which are connected to the top of the void 12 formed between the pipes 7 and 6a and can adjusts pressures.