Rotary apparatus used for an intensification of hydromechanical and mass-transfer processes in various industries can be applied successfully also as a heat generator. The purpose of present article: research of the Rotary apparatus operation as a heat generator at gelatinization of starch. It was used a Rotary apparatus of pulse power action of type homogeneisateur «YUMIX 3 ». The gradient of the shift speed of apparatus was 4,4·104 s-1. The water dispersion of corn starch was as an object of processing. Ratio of components is 1:20. Effectiveness of the heat-generator defined on power consumption for the electric motor and on the destruction degree of starch grains. Two mechanisms of heating a liquid in rotary heat-generator are a friction and hidrodynamique cavitation. Heating process of the water-starch dispersion in heat-generator consist in two stages. The first stage is a heating of the dispersion in an interval from 20 оС up to temperatures of the beginning of starch gelatinization (65÷70 оС). The second stage is a heating from temperature of the beginning of starch gelatinization up to 98 оС. At temperatures 20÷70 оС starch in a liquid substantially is in nongelled state and has no effect essentially on the hydrodynamics of liquid movement. Heating is realized by known mechanisms. Rate of the heating liquid is maximal. Temperature of a liquid is an important factor providing development cavitation. The moisture diffusion speed inside of starch grains grows at temperatures above 70 оС. There are the grains swelling, their destruction, particles gelatinization, their dissolution. There is an increase in viscosity of a liquid. The viscous liquid possesses an inertial motion and also cannot to form quickly enough the cavitation bubble and vortex flows. Therefore a cavitation degree in a water-starch dispersion containing gelled particles is below than in the dispersion with nongelled particles. At temperatures above 70 оС a friction is a major factor for the liquid heating. Starch has effect on the liquid flow character. Researches of power consumption for the electric motor have shown that at temperatures 70÷98 оС there is a decrease in consumed energy on 15÷18 %. It is indicated both to reduction in the turbulization and vortex formations, to a transitive and laminar mode of a liquid flow in the apparatus that testifies to reduction of hydraulic resistance of the apparatus. Expansion of transitive and laminar area of flow is caused by swollen, gelled, easily deformable particles of starch and molecular associates. The degree of reduction in hydraulic resistance is in immediate dependence on a degree of particles gelatinization. Conclusions: Heat generation ability of the apparatus depends on properties of a liquid and hydraulic friction. Reduction in hydraulic resistance leads to decrease in heat productivity of the apparatus. The best parameters of heating of the water-starch dispersion are reached at temperatures below 70 ºC.