An adapter for endoscope includes: an image pickup device driving signal generation circuit; an image signal output circuit; an endoscope identification information reception circuit receiving endoscope ID information; a ROM storing adapter ID information about the adapter; a flash memory storing parameters for adjustment; and a control section performing control to store the parameters for adjustment into the flash memory according to a command from a processor to write the parameters for adjustment, and read the parameters for adjustment stored in the flash memory and output the parameters for adjustment stored in the flash memory to the processor according to a command from the processor to read the parameters for adjustment.