A control device for an internal combustion engine equipped with a supercharger, which is a control device used in an internal combustion engine equipped with a supercharger that can change a supercharging pressure by operation of an actuator, and configured to operate the actuator so that a measured supercharging pressure (Picm) obtained by a supercharging pressure sensor reaches a target supercharging pressure (Pict), comprising: means for acquiring a measured value (mafm) of an air flow rate in an intake passage of the internal combustion engine, and calculating an estimated supercharging pressure (Pice) based on the measured air flow rate (mafm); means for setting a first abnormality flag when a first simultaneous inequality is established, which is a simultaneous inequality evaluating magnitude correlation between the measured supercharging pressure (Picm), the target supercharging pressure (Pict) and the estimated supercharging pressure (Pice) and is not established when the supercharging pressure sensor is normal; and means for setting a second abnormality flag when a second simultaneous inequality is established, which is a simultaneous inequality evaluating magnitude correlation between the measured supercharging pressure (Picm), the target supercharging pressure (Pict) and the estimated supercharging pressure (Pice), is not established simultaneously with the first simultaneous inequality, and is not established when the actuator is normal; characterized in that: the first simultaneous inequality is a combination of an expression that indicates that a magnitude of a difference between the measured supercharging pressure (Picm) and the estimated supercharging pressure (Pice) is larger than a first threshold value, and an expression that indicates that signs of respective errors of the measured supercharging pressure (Picm) and the estimated supercharging pressure (Pice) with respect to the target supercharging pressure (Pict) are different signs, and the second simultaneous inequality is a combination of an expression that indicates that a magnitude of a difference between the target supercharging pressure (Pict) and the measured supercharging pressure (Picm) is larger than a second threshold value, and an expression that indicates that signs of respective errors of the measured supercharging pressure (Picm) and the estimated supercharging pressure (Pice) with respect to the target supercharging pressure (Pict) are same signs. means for acquiring a measured value (mafm) of an air flow rate in an intake passage of the internal combustion engine, and calculating an estimated supercharging pressure (Pice) based on the measured air flow rate (mafm); means for setting a first abnormality flag when a first simultaneous inequality is established, which is a simultaneous inequality evaluating magnitude correlation between the measured supercharging pressure (Picm), the target supercharging pressure (Pict) and the estimated supercharging pressure (Pice) and is not established when the supercharging pressure sensor is normal; and means for setting a second abnormality flag when a second simultaneous inequality is established, which is a simultaneous inequality evaluating magnitude correlation between the measured supercharging pressure (Picm), the target supercharging pressure (Pict) and the estimated supercharging pressure (Pice), is not established simultaneously with the first simultaneous inequality, and is not established when the actuator is normal; characterized in that: the first simultaneous inequality is a combination of an expression that indicates that a magnitude of a difference between the measured supercharging pressure (Picm) and the estimated supercharging pressure (Pice) is larger than a first threshold value, and an expression that indicates that signs of respective errors of the measured supercharging pressure (Picm) and the estimated supercharging pressure (Pice) with respect to the target supercharging pressure (Pict) are different signs, and the second simultaneous inequality is a combination of an expression that indicates that a magnitude of a difference between the target supercharging pressure (Pict) and the measured supercharging pressure (Picm) is larger than a second threshold value, and an expression that indicates that signs of respective errors of the measured supercharging pressure (Picm) and the estimated supercharging pressure (Pice) with respect to the target supercharging pressure (Pict) are same signs. the first simultaneous inequality is a combination of an expression that indicates that a magnitude of a difference between the measured supercharging pressure (Picm) and the estimated supercharging pressure (Pice) is larger than a first threshold value, and an expression that indicates that signs of respective errors of the measured supercharging pressure (Picm) and the estimated supercharging pressure (Pice) with respect to the target supercharging pressure (Pict) are different signs, and the second simultaneous inequality is a combination of an expression that indicates that a magnitude of a difference between the target supercharging pressure (Pict) and the measured supercharging pressure (Picm) is larger than a second threshold value, and an expression that indicates that signs of respective errors of the measured supercharging pressure (Picm) and the estimated supercharging pressure (Pice) with respect to the target supercharging pressure (Pict) are same signs.