To provide a preservation method of acetobacter fit for long preservation, stable in lag time and thereby capable of being produced on an accurate schedule, usable for any vinegar production and excellent in versatility.

The preservation method of acetobacter includes a first dilution step, a centrifugation and second dilution step, a freezing step and a preservation step. In the first dilution step, a fermentation liquid during the acetic fermentation by submerged culture is harvested and diluted by added with a dilution solvent so that the acetic acid concentration is ≤4% by weight/volume. In the centrifugation and second dilution step, the acetic acid fermentation liquid diluted in the first step is centrifuged and added with a dilution solvent to be diluted so that the acetic acid concentration is ≤0.1% by weight/volume. In the freezing step, the acetobacter-containing liquid whose acetic acid concentration is made to be ≤0.1% by weight/volume through the centrifugation and second dilution step is frozen. In the preservation step, the acetobacter-containing liquid frozen through the freezing step is preserved at ≤-5°C.