An endoscope system, including a plurality of processor devices, each of which having a detachably attached endoscope, and a controller device, which is communicably connected with the plurality of processor devices, is provided. The controller device is capable of outputting at least one of an activating signal to activate at least one of the processor devices and an inactivating signal to inactivate at least one of the processor devices to the at least one of the processor devices. Each of the plurality of processor devices includes a first power supplying unit to supply the processor device with activating power, a power supply controlling unit, which is driven by preparatory power and is capable of at least one of switching on the first power supplying unit and switching off the first power supplying unit, and a second power supplying unit to supply the preparatory power to the power supply controlling unit.
