To improve the stating performance of an in-cylinder aerobic fuel injection type internal combustion engine involving a fuel injector for its cylinder connected with a fuel feed line and an air feed line, without increasing the size of the internal combustion engine.

An exhaust passage 11 led from a cylinder is provided with an exhaust switch valve 18, and a sub air feed line 19 which connects the exhaust passage 11 and an air feed line 14 together is provided with an air switch valve 20. The exhaust switch valve 18 and the air switch valve 20 are adapted to be closed and opened respectively when a starting switch 24 is turned on, and to be opened and closed reversely when the pressure in the air feed line 14 reaches a predetermined feed pressure with the starting switch 24 being held on.