The objective of the present invention is to provide an engine system control device capable of stabilizing the combustion state while improving fuel consumption by heating the intake air. The presentinvention is a control device for an engine system equipped with an engine that burns an air-fuel mixture of air and fuel, an intake air path that draws air into the engine, and an intake air heatingmechanism that heats the intake air. This control device is characterized in that the amount of heating of the intake air is controlled in accordance with the combustion speed of the air-fuel mixture.