A processing device 3 of an endoscope system 1 according to the present invention includes: an image processing unit 31 including an FPGA a configuration memory 32 that stores a plurality of pieces of configuration data corresponding to respective contents of image processes that are performed in accordance with imaging sensors 25 of endoscopes 2 to be attached and a configuration controller 33a that performs control to subject the FPGA of the image processing unit 31 to reconfiguration using the piece of configuration data that depends on the imaging sensor 25 of the attached endoscope 2 among the plurality of pieces of configuration data stored in the configuration memory 32.
