To provide an endoscope washer with the little possibility of forgetting to attach a waterproof cap to the electric connector part of an endoscope when washing the endoscope.

The endoscope washer is provided with fixed waterproof caps 6 and 7 for watertightly isolating the electric contacts 272 and 282 of the electric connector parts 27 and 28 from a washing tub 2 by inserting the electric connector part 27 and 28 of the endoscope 20 to the inner peripheral part of an outer wall 3 surrounding the periphery of the washing tub 2 housing the endoscope 20 which is a washing object. The waterproof caps 6 and 7 can be entirely formed of an elastic material and an O ring 71 for sealing can be mounted.