Provided is a control device for an internal combustion engine having a cylinder resting mechanism, capable of accurately detecting an intake/exhaust valve state and therefore serving to solve problems of fuel depletion and environmental conservation. The control device includes: ignition means 2 including high voltage means 202 for causing ignition discharge on an ignition plug based on an ignition signal, and an ignition discharge parameter detection circuit 203 for detecting a parameter indicating a state of the ignition discharge; and valve state determination means 206 for determining a valve operation state of an intake/exhaust valve based on at least one of an ignition discharge duration, ignition insulation breakdown voltage, and ignition discharge maintaining voltage detected based on an output signal from the ignition discharge parameter detection circuit 203. Operation of cylinder resting control means 207 is controlled based on a determination result by the valve state determination means 206.