Provided is an attachment for an endoscope, the attachment being attached to a leading end part of the endoscope having a leading end surface on which an observation window for observing an inside of a subject's body and a first opening for jetting a constant-pressure supplied gas are formed, the attachment including: a second opening provided at a position separate from the leading end surface； a pipe conduit that communicates the first opening and the second opening with each other so as to jet the constant-pressure supplied gas from the second opening； and a region separating member that separates a jetting region of the constant-pressure supplied gas jetted from the second opening from a region of view of the observation window.
