PROBLEM TO BE SOLVED: To provide an endoscope cleaning attachment with which cleaning and disinfection work can be quickly performed by reliably supplying a cleaning liquid or the like to a target site in the housing chamber of the endoscope distal end structure part, where the treatment instrument standing base is rotatably housed.SOLUTION: A endoscope cleaning attachment 30 comprises: an attachment body 50 detachably attached to an endoscope distal end structure part 11 of an insertion part 2 and a housing chamber cleaning body 31. The housing chamber cleaning body 31 comprises: an engaging part 36 which can be detachably attached, through a channel opening 22 of a treatment instrument insertion channel 20 leading to a housing chamber 15a of an endoscope distal end structure part 11, to within a channel hole 23, to block the communication between the channel 20 and the housing chamber 15a and a body part 35 which includes a first flow channel 33 having an opening in a connection part end surface with a flange 31f, and a flow channel 32 arranged to cross the first flow channel 33 and having a second flow channel 34 with one end opening leading to the first flow channel 33 and with the other end opening of 34 m2.
