An analyzer that determines blood viscosity at different shift speed has been designed. Its operation principle is based on the use of rotation viscosity measurement using a rotor freely floating in the sample. A blood sample is placed between the stationary thermostabilized measuring cylinder and a free floating rotor. The system creates a rotating magnetic field which makes the rotor rotate with a preset speed, determines shift stress, calculates the magnitude of viscosity and indicates it on the display. The magnitude of viscosity is proportional to the square of the current drawn in the windings of a stator, which divided by the rotational speed of a rotor. The analyzer provides viscosity measurements in the range of 0.7-14 mPa.sec at shift rate of 20-200 sec-1, the sample volume is less than 1 cm3. The device can be used for the diagnosis of the diseases whose pathogenesis microcirculatory and coagulative disorders play an important role in.