An ozone generating apparatus for making a temperature distribution in a dielectric tube more uniform including a sealed vessel, two tube sheets made of a conductive metal plate having a hole formed therein which are provided at a predetermined interval to divide the inside of the sealed vessel into three spaces; a metal tube formed so as to connect holes of the tow tube sheets, a dielectric tube which is inserted into the inner part of a dielectric tube so as to have a predetermined gap between an outer wall an inner wall of a metal tube and a metal electrode formed inside the dielectric tube. An alternating current voltage is applied between the tube and electrode, a gas including oxygen flowing in a gap is discharged to generate ozone, and a discharge suppressing member is provided at a part of the gap facing a tube sheet.