An object of the present invention is to provide a barrier discharge device capable of increasing the combustion efficiency of an engine while overcoming the problems of the cumbersome replacement of the electrodes and the commercialization of the device. The barrier discharge device of an engine includes a dielectric body and at least two barrier discharge electrodes which are held inside the dielectric body and to which voltages for barrier discharge are applied, wherein each of the barrier discharge electrodes are not exposed to the inside of a cylinder bore and are arranged so as to surround the cylinder bore.