To eliminate the non-smooth operation attributable to the irregular combustion between a plurality of cylinders of an alcohol engine which is operated with methanol, etc., difficult to burn as the fuel, and to reduce the vibration and noise.

An exhaust gas temperature sensor 40 is fitted to an exhaust gas branch close to an exhaust port 30 at an exhaust manifold of a multiple cylinder engine. An opening/closing valve 44 is provided at least on an intake passage of a cylinder whose exhaust gas temperature is higher than the mean value of the exhaust gas temperature of a plurality of cylinders, the deviation between the mean value of the exhaust gas temperature and the exhaust gas temperature of the cylinder having the opening/closing valve 44 is calculated, and the opening of the opening/closing valve 44 is controlled so that the deviation is zero or within the allowable temperature deviation.