PURPOSE: To prevent the occurrence of bad operation due to accumulation of exhaust carbon or the like mixed in intake air for an actuator operated to open and close a turbo charger control valve disposed on the downstream side of a pressure wave turbo charger according to the supercharging pressure.

CONSTITUTION: A by-pass passage 13 for by-passing a pressure wave turbo charger 4 to open at the time of starting and an actuator 23 operated to open and close a turbo charger control valve 22 interposed in an intake passage 2 according to the magnitude of supercharging pressure are provided in such a manner that the introduction of supercharging pressure to the actuator 23 and the supply of by-pass air through the by-pass passage 13 are performed through a common opening portion 25 communicated with the intake passage 2, and carbon flowing into the actuator 23 is flown out by by-pass air.