To provide an engine control device capable of reducing fuel consumption without reducing a travel speed in constant speed travel.

In a vehicle mounted with a belt type continuously variable transmission 2, this engine control device determines a constant speed travel state of the vehicle from a variation in accelerator opening Acc and a variation in the travel speed V of the vehicle, and reduces a supply quantity of a combustion component to an engine by a preset predetermined quantity when determining the constant speed travel state of the vehicle. Thus, consumption of engine torque can be reduced by a hydraulic pressure reducible quantity for sandwiching a belt by the continuously variable transmission 2 and a belt slide reducible quantity. After determining the constant speed travel state of the vehicle, when a separation component from a constant speed travel speed V_AV of the travel speed of the vehicle falls within a preset range, and a variation in the accelerator opening falls within a preset range, the supply quantity of the combustion component to the engine is respectively reduced by the preset predetermined quantity every time when a preset predetermined time passes.