FIELD: physics. SUBSTANCE: nvention relates to engineering physics, particularly to determination of parameters of metal melts. Smoke detecting device in laboratory electric furnace, which is part of water-cooled vacuum furnace, filled with inert gas, comprises electric furnace branch pipe, vacuum hose and pump, smoke detector, which comprises at least one photosensor, the output of which is connected to a communication channel, the output of which is connected to the computer, the transparent tubular element on which the smoke detector is placed, is located between the vacuum hose and the electric furnace branch pipe. EFFECT: technical result is possibility of functioning and preservation of objectivity of assessment of smoke optical characteristics when studying sample without damage of smoke detector.