PROBLEM TO BE SOLVED: To provide an endoscope cleaning and disinfecting apparatus capable of uniformly polishing electrode sensors to easily maintain the accuracy of measuring a chemical concentration.SOLUTION: An endoscope cleaning and disinfecting apparatus comprises: a sensor container 3a which has a first fluid introduction port 3d and a second fluid introduction port 3e both being opening, and in which the fluid introduced from the first fluid introduction port 3d circulates in a forward direction A and the fluid introduced from the second fluid introduction port 3e circulates in a reverse direction B opposite to the forward direction A electrode sensors 3p, 3m which are disposed such that their axial directions are perpendicular to the forward direction A and the reverse direction B, and which measure the concentration of a chemical introduced as a fluid into the sensor container 3a and granular cleaning particles 3b which are sealed within the sensor container 3a and polish the electrode sensors 3p, 3m in the forward direction A and the reverse direction B, riding the flow of the fluid.
