An endoscope washing and disinfecting apparatus of the present invention includes a first channel member in which a projection portion abuts on a fitting surface in a channel mouthpiece, and a first channel internally provided communicates with a suction channel inside the channel mouthpiece, a second channel member which is fitted and fixed to an outer periphery of the first channel member, and is internally provided with a second channel which communicates with the first channel, a pressing member which is provided in the second channel, and presses the first channel member to the channel mouthpiece side in the second channel, and a liquid introduction port which is formed in the second channel member and introduces a liquid to the second channel.
