PURPOSE: To abate the extent of variations in an intake charging quantity at a low load range in particular as well as to secure combustion stability by interconnecting a lot of independent intake passages with one another, and interrupting this interconnected state only in an overlap period between an intake period and an exhaust one.

CONSTITUTION: An intake passage 6 of an engine consists of an intake manifold 13, forming an independent intake passage 12 at each cylinder 2. In this independent intake passage 12, there is provided with a second throttle valve 25 which controls an intake flow rate. In this case, the whole part of this independent intake passage 12 is interconnected through one interconnecting pipe 30. In a connecting pipe 30a connecting this independent intake passage 12 to the interconnecting pipe 30, there is provided with a solenoid valve 31 opening or closing this connecting pipe. In addition, the solenoid valve 31 is controlled by a control unit U on the basis of each detection signal out of various sensors 35-37. At this time, the interconnecting pipe 30 is closed only in an overlap period between an intake period and an exhaust one.