The present invention provides a barium titanate having a small particle size, containing small amounts of unwanted impurities, and exhibiting excellent electric characteristics, which can be employed for forming a dielectric ceramic thin film required for a small-sized capacitor which enables production of a small-sized electronic apparatus; and a process for producing the barium titanate. When a titanium oxide sol is reacted with a barium compound in an alkaline solution containing a basic compound, the basic compound is removed in the form of gas after completion of reaction, and the resultant reaction mixture is fired, a barium titanate having a large BET specific surface area and a high tetragonality content is produced.