The present disclosure relates to a modular simultaneous diagnosis PCR system, and more particularly, to a modular simultaneous diagnosis PCR system, in which a plurality of seating grooves, in which biochips are seated, is formed in an upper surface of a single main body housing, a plurality of heating/cooling modules and a plurality of light source modules are installed in the main body housing so as to correspond to the seating grooves, a plurality of cover members including detection modules corresponding to the seating grooves is installed on an upper surface of the main body housing so as to be rotatable upward or downward, and a PCR inspection is simultaneously performed on samples accommodated in multiple biochips by controlling the plurality of heating/cooling modules, the plurality of light source modules, and the plurality of detection modules in an integrated manner by using a single control module installed in the main body housing, such that a plurality of PCR processes may be conveniently performed, maintenance costs may be reduced, and product prices may be lowered by eliminating duplicated components.