PROBLEM TO BE SOLVED: To provide a silica dispersion that maintains antifungal properties for the long term and can prevent the deterioration of polishing performance.SOLUTION: In one or plural embodiments, a silica dispersion comprises a silica particle, water and a preservative, where the preservative is selected from the group consisting of (A) a compound having a 5 membered ring or 6 membered ring structure comprising >N-C-N< in a ring, (B) a compound comprising an aldehyde group, and a combination of them.SELECTED DRAWING: None