In an engine torque calculation method, basic engine torque TQb is
calculated based on an engine rotational speed Ne and a fuel injection
amount Q, and the basic engine torque TQb is corrected using a
predetermined parameter (e.g., an intake air amount Q) which has an
influence on engine torque, whereby engine torque TQact is calculated. A
torque sensitivity coefficient K1 corresponding to an amount of change in
the engine torque TQact when the parameter changes by a unit amount is
calculated based on the engine rotational speed Ne and the fuel injection
amount Q, and the engine torque TQb is corrected using the torque
sensitivity coefficient K1.