PROBLEM TO BE SOLVED: To provide rinse water for a medical endoscope with little change over time.SOLUTION: Rinse water is alkali ion water for cleaning an observation window of an endoscope having pH of 9.0-12.0, and includes at least one of a polyphosphate, a silicate, silicate particles, titanium oxide particles, or aluminum oxide particles of 1-10 ppm as an additive, and further includes nanobubbles, with a mode diameter of 50-500 nm, of 100,000 bubbles/mL or more.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2016,JPO&INPIT【課題】経時変化の小さい医療用内視鏡用洗浄水の提供。【解決手段】内視鏡の観察窓を洗浄するための、ｐＨ９．０～１２．０のアルカリイオン水であって、添加剤として、ポリリン酸塩、ケイ酸塩、ケイ酸塩粒子、酸化チタン粒子、または酸化アルミニウム粒子の少なくともいずれかを１～１０ｐｐｍ含む洗浄水。更に、モード径５０～５００ｎｍのナノバブルを１０万個／ｍＬ以上含む洗浄水。【選択図】図３
