The invention relates to the technical field of medical instruments, in particular to a cleaning and disinfecting tank and a cleaning and disinfecting machine for an endoscope. The cleaning and disinfecting tank comprises a tank body and a tank cover matched with the tank body, the tank body and the tank cover form a closed cleaning and disinfecting chamber, the endoscope is cleaned and disinfected in the cleaning and disinfecting chamber through a cleaning fluid and a disinfecting fluid correspondingly, the middle part of the tank cover is sunken downwards, the downward-sunken part extends into the tank body and is used for downwards pressing the endoscope into the cleaning fluid or the disinfecting fluid. According to the cleaning and disinfecting tank, the downward-sunken part is used for downwards pressing the endoscope, so that the endoscope is completely immersed in the cleaning fluid or the disinfection fluid, then the endoscope can be comprehensively cleaned, meanwhile, the downward-sunken part which is in contact with the endoscope can also be in contact with the cleaning fluid or the disinfecting fluid, cleaning and disinfecting of the downward-sunken part are realized, the problem that due to pollution caused by the fact that residual stains are left on the tank cover to the endoscope, the endoscope is not disinfected to reach the qualified standard is solved, and the cleaning efficiency and the cleaning effect of the endoscope are improved.