In a control apparatus, when an engine is cranked, “an air-fuel mixture (an air-fuel mixture used for determination of fuel property) including fuel in a first predetermined fuel amount TAUm and air in a first predetermined air amount Mcm”, which generates torque that does not make the engine autonomously operate, is formed in a first cylinder (cylinder used for determination of the fuel property), and the air-fuel mixture is ignited and combusted by a spark at an ignition timing after a compression top dead center. Further, the control apparatus determines “an amount of heat generated per unit mass of the fuel” when the air-fuel mixture is combusted in the first cylinder, and determines a property of the fuel based on the amount of generated heat.