Method for producing isopropyl alcohol by continuous culture

A method of producing isopropyl alcohol includes: culturing an isopropyl alcohol-producing Escherichia coli under a bacterial cell growth condition in which the Escherichia coli stably proliferates in an isopropyl alcohol production period while continuously supplying a substrate solution to a culture tank and continuously removing a product-containing culture solution from the culture tank, the substrate solution containing a plant-derived raw material, the number of cells of the isopropyl alcohol-producing Escherichia coli in the culture tank being maintained during the culturing, and the isopropyl alcohol-producing Escherichia coli having isopropyl alcohol production ability introduced or modified by genetic recombination; bringing the isopropyl-alcohol-producing Escherichia coli into contact with the plant-derived raw material in the culture tank to produce isopropyl alcohol; and recovering the isopropyl alcohol produced by the isopropyl alcohol-producing Escherichia coli from the culture solution that contains the product and that has been removed from the culture tank.