An apparatus for carrying out an enzymatic cycling reaction including a turntable (3) arranged in a reaction tank (1), a number of reaction vessels (2) being arranged in the turntable along its periphery, a device (6, 7) for circulating an antifreeze liquid through the reaction tank (1), a heater (9) for heating the antifreeze liquid, a refrigerator (10), for cooling the antifreeze liquid and a switching valve (8) for selectively passing the antifreeze liquid through the heater (9) or refrigerator (10). Until all the samples and cycling mixture are delivered into the reaction vessels, the reaction tank (1) is held at a very low temperature at which no enzymatic cycling reaction proceeds. Then the antifreeze liquid is heated to an enzymatic cycling reaction temperature so as to perform the enzymatic cycling reaction simultaneously for liquids contained in all the reaction vessels for a desired period. Then, the antifreeze liquid is heated to a high temperature so as to stop simultaneously the cycling reaction in all the reaction vessels.