To make compatible both the inhibition of the generation of unburnt gas and the reduction of an engine brake force.

An engine control device 19 controls the operation of an engine during deceleration traveling, and when deceleration traveling is determined, the device sets an intake air amount supplied to the engine 12 at a deceleration intake air amount larger than a normal intake air amount which is normally set according to an output demand and sets the number of combustion cylinders according to a traveling state while making one or more combustion cylinders supplied with fuel exist.