A bypass passage (34) is to an exhaust gas pipe (24) connected in such a manner, so as to bypass a turbine wheel (32). A bypass valve (35), the supercharging pressure adjusts a is in the bypass passage (34) provided. A ECU (35) a calculated real estate tax value of said bypass valve (35) according to a motor drive condition. The ECU (35) calculates an actual loading efficiency of the turbocharger (30). And then the ECU corrects (35) of said bypass valve the real estate tax value (35), based on a comparison between a target- loading efficiency and a Is- loading efficiency.