The utility model provides a boundary's level gauge, a liquid level that is used for two kind at least liquid in the measuring vessel, different liquid have different density, boundary's level gauge includes cylindric stock solution chamber, two at least magnetic floater that can freely remove from top to bottom at the stock solution intracavity and the indicator that is used for surveing magneticfloater's position, the stock solution chamber has at least one inlet with the container intercommunication, different inlet respectively with the container in correspond different liquid the position communicate, a magnetic floater's density is lighter than the density of the minimum liquid of two kind at least liquid middle density, between the density of density different liquid in at least two kinds liquid of the 2nd magnetic floater, the indicator that lies in side in stock solution chamber includes a plurality ofly along the stock solution chamber direction of height transparent check of looking that the stack was arranged about in proper order, and the sign iron powder is equipped with in the check to transparent looking, and the sign iron powder can be under magnetic floater's magnetic force be adsorbed on the extremely transparent observation face of looking side of check. This boundary's level gauge respective liquid level of different liquid in can measuring vessel.