This endoscope system comprises an endoscope and a washing apparatus. The endoscope is provided with an elongate insertable part having an observing window and illuminating window in the tip part, an observing system receiving the returning light from an object entering through the observing window, an illuminating light output system emitting an illuminating light from the illuminating window and a memorizing device capable of memorizing information relating to washing. The washing apparatus is provided with a read-out device reading out information memorized in the memorizing device of the endoscope and a control device controlling the conditions of washing the endoscope by the information read out by the read-out device.