To ensure an intake pipe negative pressure required for the operation of negative pressure-using equipment without providing an air pump in a system for performing an intake air quantity control by variably controlling an intake valve.

In general, the lift quantity of the intake valve 28 is controlled so that the actual air quantity charged into a cylinder is a target air quantity in the state where a throttle valve 15 is largely opened so that the intake pipe negative pressure gets close to the atmospheric pressure to reduce pumping loss (intake resistance), whereby the fuel consumption is improved. In any one case of fuel cut, speed-reducing operation, and idle operation, the air quantity suckable into the cylinder is increased by increasingly controlling the lift quantity of the intake valve 28, and the throttle opening is narrowed by this portion to increase the intake resistance, whereby the negative pressure generated on the downstream side of the throttle valve 15 is efficiently increased to ensure the intake pipe negative pressure required for the operation of a brake booster 52 or an evaporated fuel treatment device 50.