An internal combustion engine is provided with a variable valve train capable of altering opening and closing timings and/or opening amounts of at least one of an intake valve and an exhaust valve of an internal combustion engine. The internal combustion engine is characterized in that the internal combustion engine is further provided with a negative pressure mechanism that operates using intake pipe negative pressure generated in an intake passage of the internal combustion engine, a throttle valve for adjusting the flow rate of intake air flowing through the intake passage, and negative pressure generating device that controls at least one of the variable valve train and the throttle valve to generate the intake pipe negative pressure, when the intake pipe negative pressure for operation of the negative pressure mechanism is insufficient.