A storage unit provided in an engine control device stores three kinds of mode maps having different engine output characteristics. One of the mode maps is selected in accordance with the driving conditions, and a target torque is set by referring to the selected mode map using an engine speed and an accelerator opening-degree as parameters. A throttle opening-degree signal corresponding to the target torque is output to a throttle actuator, and an operation of opening or closing the throttle valve is performed in response to the throttle opening-degree signal.