1. In a variable valve type internal combustion engine having cylinders and electromagnetically actuated intake and exhaust valves arranged for each cylinder, the intake air amount fed to the cylinder being controlled by controlling the close timing of the intake valve, a control system for controlling the engine, comprising: an operation range judging section that judges an operation range assured by the engine; a variable cycle operating section that switches the operation of the engine between 4-cycle operation and a different cycle operation in accordance with the judgment made by said operation range judging section, said different cycle operation being of an operation whose cycle is different from the 4-cycle; and an intermediate variable cycle operating section that allows part of the cylinders of the engine to carry out 4-cycle operation and the remaining part of the cylinders to carry out said different cycle operation when said operation range judging section judges that the engine is under an intermediate operation range between an operation range provided by said 4-cycle operation and an operation range provided by said different cycle operation.