This invention relates to a vehicle engine control unit suitable for use in an automobile. When a step-on detection signal is outputted from accelerator pedal operation state detection means (81), first controlled variable setting means (82) sets the controlled variable of engine output regulation means (7) in accordance with a manipulated variable detection signal and when a step-on release detection signal is outputted from the accelerator pedal operation state detection means (81), second controlled variable setting means (86) receives the output of a constant speed driving speed designation signal from driving state designation means (83) and sets the controlled variable of the engine output regulation means (7) necessary for making the driving speed of a vehicle equal to a target speed on the basis of the driving speed detection signal from driving speed detection means (85). When an acceleration driving designation signal is outputted from the driving state designation means (83) described above, the second controlled variable setting means (86) sets the controlled variable of the engine output regulation means (7) necessary for the vehicle to make acceleration driving. Particularly because the second controlled variable setting means (86) sets a controlled variable which serves to vary vehicle in accordance with the time and the vehicle speed, the speed change of the vehicle can be made smoothly through the engine output regulation means (7) operating on the basis of this controlled variable.