To provide a control device for an internal combustion engine that can optimally control a plasma ignition operation independent of fuel type. In a control device 30 of an internal combustion engine 20, which controls plasma ignition operation for causing volume ignition of air fuel mixture by plasma in a combustion chamber 10, a fuel type detection part 40 detects a type of fuel to be supplied to the combustion chamber 10. According to the detected fuel type, a state of plasma or a state of air fuel mixture in the combustion chamber 10 is controlled.