A thermocycling device for processing biological or chemical samples, comprising: a reaction vessel receiving element comprising a plurality of segments made from metal, the segments being fixed in position by a clamping frame made from non heat conducting material, each segment (8b, 8c) having a plurality of reaction vessel holders; a plurality of temperature equalization plates, each temperature equalization plate being provided in the area beneath one of the plurality of segments so that in the area beneath each of the plurality of segments one temperature equalization plate is provided, each temperature equalization plate being a flat element with a surface corresponding to the basic surface of the segment beneath which it is provided and being a hollow body with a small amount of fluid, a plurality of separately actuable Peltier elements, at least one Peltier element being provided in the area beneath each of the plurality of temperature equalization plates; a cooling element, extending over the area of the plurality of segments, the cooling element being provided below the Peltier elements a plurality of heat conducting foils, each provided between a respective segment and a respective temperature equalization plate; between a respective temperature equalization plate and a respective Peltier element, and between a respective Peltier element and the cooling element, a plurality of power amplifiers (58, 59) configured to provide current to the plurality of Peltier elements; a plurality of switches (56, 57), each switch being associated with a power amplifier; a controller configured to control the plurality of switches (56, 57) to direct current flow from any of the plurality of power amplifiers (58, 59) to any of the plurality of Peltier elements so that a ramp rate to control the temperature in each one of the segments can be varied as desired; wherein each temperature equalization plate is comprised of a gastight jacket and the pressure in the hollow body is so low that the fluid is in a state of equilibrium between the liquid and the gaseous aggregate state so that it evaporates at a warmer section of the temperature equalization plate and condenses at a cooler section. a reaction vessel receiving element comprising a plurality of segments made from metal, the segments being fixed in position by a clamping frame made from non heat conducting material, each segment (8b, 8c) having a plurality of reaction vessel holders; a plurality of temperature equalization plates, each temperature equalization plate being provided in the area beneath one of the plurality of segments so that in the area beneath each of the plurality of segments one temperature equalization plate is provided, each temperature equalization plate being a flat element with a surface corresponding to the basic surface of the segment beneath which it is provided and being a hollow body with a small amount of fluid, a plurality of separately actuable Peltier elements, at least one Peltier element being provided in the area beneath each of the plurality of temperature equalization plates; a cooling element, extending over the area of the plurality of segments, the cooling element being provided below the Peltier elements a plurality of heat conducting foils, each provided between a respective segment and a respective temperature equalization plate; between a respective temperature equalization plate and a respective Peltier element, and between a respective Peltier element and the cooling element, a plurality of power amplifiers (58, 59) configured to provide current to the plurality of Peltier elements; a plurality of switches (56, 57), each switch being associated with a power amplifier; a controller configured to control the plurality of switches (56, 57) to direct current flow from any of the plurality of power amplifiers (58, 59) to any of the plurality of Peltier elements so that a ramp rate to control the temperature in each one of the segments can be varied as desired; wherein each temperature equalization plate is comprised of a gastight jacket and the pressure in the hollow body is so low that the fluid is in a state of equilibrium between the liquid and the gaseous aggregate state so that it evaporates at a warmer section of the temperature equalization plate and condenses at a cooler section.