To provide an endoscope washing device that can prevent the occurrence of clogging in a liquid feed tube due to additives contained in additive liquid poured into an additive bottle.SOLUTION: An additive bottle of an endoscope washing device has a bottle body 200 with additive liquid 250 poured therein, and a lid 300 detachably attached to the bottle body. The lid includes a valve 342 for making the additive liquid flow into a liquid containing part 403 and to a water inlet 332, a valve core 341 extending from the valve to the downside and biased by a spring to an upper part, and a check valve mechanism having a valve seat which the valve is abutted with. The valve seat is an opening end 310a extending to the upper part so as to surround a water intake 332 from an inner side of the lid, and of an inflow barrier 310 for preventing inflow of additives 251 contained in the additive liquid to a liquid receiving part. The additive liquid flowing into the liquid absorbing part is sucked up through a liquid feed tube 220, and the lower end of the valve core comes in abutment with a protruding portion 407, and thereby the valve is opened separately from the valve seat to the upper part.SELECTED DRAWING: Figure 22
