Disclosed is a thermal cycler (1).The Thermal cycler (1) comprises a polymerase chain reaction (PCR) module (10) having a plurality of receiving grooves for receiving a plurality of microplates (12) in which biological or chemical samples are received; a base body (30) having a module receiving part formed on its upper area and receiving the PCR module (10) therein; and an upper cover (40) for covering an upper opening of the PCR module (10), wherein the microplate receiving grooves are inclined relative to a plane of PCR module (10). With this configuration, the thermal cycler (1) according to the present invention is capable of amplifying nucleic acids of the large number of samples in a compact area simultaneously under a constant temperature within a short period of time at desired angles.
