CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

A control device of an internal combustion engine in a simple configuration capable of finely detecting the combustion state of the internal combustion engine, for example, an occurrence of knocking from an ionic current signal is provided. A control device 20 of an internal combustion engine 100 having an ionic current value detection unit 42 that detects an ionic current value during combustion including an ionic current signal processing unit 201 that performs signal processing of the ionic current value and a detection unit 20m that detects a combustion state of the internal combustion engine 100 based on a processing result by the ionic current signal processing unit 201, wherein the ionic current signal processing unit 201 includes a differentiating unit 201a that calculates a differential value of the ionic current value is provided.