Provided is a control device for an internal combustion engine equipped with a supercharger, including: operation state detection means for detecting an operation state of the internal combustion engine; overlap read means for reading a valve overlap period; collector pressure detection means for detecting a collector pressure; exhaust gas pressure estimation means for estimating an exhaust gas pressure on an upstream side of the supercharger; and scavenging amount estimation means for estimating a scavenging amount based on the operation state, the valve overlap period, the collector pressure, and the exhaust gas pressure.