The sensor element for determining of the mercury vapors on the basis of the thin semi-conductor-HgS film is developed. Deposition of films was carried out on pre-degreased polycrystalline glass substrate 30x16 mm in size. The compositions of the reaction mixture consisted of nitrate mercury Hg(NO3)2, thiocarbamidum N2H4CS, aqueous solution of ammonia NH3·H2O, potassium dichromate K2Cr2O7, sodium sulfite Na2SO3. It was found that the optimal conditions for the synthesis of the films are: temperature 60 °C, with the introduction of a reaction mixture of additive of salt potassium dichromate in numberof 3·10-3 mol/L. The thickness of the received the hydrargyrum sulphide film was 0.5-0.6 microns. On the basis of the received HgS layer sensor elements were made with an sensitive area of the sensor element 5-5 mm. Ohmic contacts for them were formed from electrochemically deposited nickel layer is about 1 micron thick. As a response of the sensor elements hydrargyrum used the change of ohmic resistance. Thus, as a rule, there occurs its decrease, that speaks about adsorption donor character interaction with mercury film. Concentration dependence of the response of the sensor elements in a range mercury vapor concentrations up of 0.09 to 20 mg/m3 is constructed. The threshold concentration of vapors providing confident determination of mercury for 2-5 minutes was about 0.09 mg/m3, which creates the possibility of its rapid detection in air hazardous to human health concentrations. The reversible adsorption of mercury vapors sensor elements based on chemically deposited HgS films is established that speaks about a possibility of their reusable use. For reduction of regeneration time of sensor elements after contact with the mercury vapors suggested their heating to temperatures of 70-90 °C for 10-15 seconds. The developed sensor element is of interest to an express kontrol for mercury vapors in the air at its floods, other contingency situations and can find application as a part of analyzers, compact and available at the price.